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Thompson KM, Kalkowska DA, Kidd SE, Burns CC, Badizadegan K. Trade-offs of different poliovirus vaccine options for outbreak response in the United States and other countries that only use inactivated poliovirus vaccine (IPV) in routine immunization. Vaccine 2024; 42:819-827. [PMID: 38218668 PMCID: PMC10947589 DOI: 10.1016/j.vaccine.2023.12.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/23/2023] [Accepted: 12/29/2023] [Indexed: 01/15/2024]
Abstract
Delays in achieving polio eradication have led to ongoing risks of poliovirus importations that may cause outbreaks in polio-free countries. Because of the low, but non-zero risk of paralysis with oral poliovirus vaccines (OPVs), countries that achieve and maintain high national routine immunization coverage have increasingly shifted to exclusive use of inactivated poliovirus vaccine (IPV) for all preventive immunizations. However, immunization coverage within countries varies, with under-vaccinated subpopulations potentially able to sustain transmission of imported polioviruses and experience local outbreaks. Due to its cost, ease-of-use, and ability to induce mucosal immunity, using OPV as an outbreak control measure offers a more cost-effective option in countries in which OPV remains in use. However, recent polio outbreaks in IPV-only countries raise questions about whether and when IPV use for outbreak response may fail to stop poliovirus transmission and what consequences may follow from using OPV for outbreak response in these countries. We systematically reviewed the literature to identify modeling studies that explored the use of IPV for outbreak response in IPV-only countries. In addition, applying a model of the 2022 type 2 poliovirus outbreak in New York, we characterized the implications of using different OPV formulations for outbreak response instead of IPV. We also explored the hypothetical scenario of the same outbreak except for type 1 poliovirus instead of type 2. We find that using IPV for outbreak response will likely only stop outbreaks for polioviruses of relatively low transmission potential in countries with very high overall immunization coverage, seasonal transmission dynamics, and only if IPV immunization interventions reach some unvaccinated individuals. Using OPV for outbreak response in IPV-only countries poses substantial risks and challenges that require careful consideration, but may represent an option to consider for some outbreaks in some populations depending on the properties of the available vaccines and coverage attainable.
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Affiliation(s)
| | | | - Sarah E Kidd
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Cara C Burns
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Chorin O, Markovich MP, Avramovich E, Rahmani S, Sofer D, Weil M, Shohat T, Chorin E, Tasher D, Somekh E. Oral and fecal polio vaccine excretion following bOPV vaccination among Israeli infants. Vaccine 2023:S0264-410X(23)00585-6. [PMID: 37268556 DOI: 10.1016/j.vaccine.2023.05.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/14/2023] [Accepted: 05/16/2023] [Indexed: 06/04/2023]
Abstract
INTRODUCTION Inactivated polio virus (IPV) vaccinations are a mainstay of immunization schedules in developed countries, while oral polio vaccine (OPV) is administered in developing countries and is the main vaccine in outbreaks. Due to circulating wild poliovirus (WPV1) detection in Israel (2013), oral bivalent polio vaccination (bOPV) was administered to IPV primed children and incorporated into the vaccination regimen. OBJECTIVES We aimed to determine the extent and timeframe of fecal and salivary polio vaccine virus (Sabin strains) shedding following bOPV vaccination among IPV primed children. METHODS Fecal samples were collected from a convenience sample of infants and toddlers attending 11 Israeli daycare centers. Salivary samples were collected from infants and toddlers following bOPV vaccination. RESULTS 398 fecal samples were collected from 251 children (ages: 6-32 months), 168 received bOPV vaccination 4-55 days prior to sample collection. Fecal excretion continued among 80 %, 50 %, and 20 %, 2, 3, and 7 weeks following vaccination. There were no significant differences in the rate and duration of positive samples among children immunized with 3 or 4 IPV doses. Boys were 2.3-fold more likely to excrete the virus (p = 0.006). Salivary shedding of Sabin strains occurred in 1/47 (2 %) and 1/49 (2 %) samples 4, and 6 days following vaccination respectively. CONCLUSIONS Fecal detection of Sabin strains among IPV-primed children continues for 7 weeks; additional doses of IPV do not augment intestinal immunity; limited salivary shedding occurs for up to a week. This data can enhance understanding of intestinal immunity achieved by different vaccination schedules and guide recommendations for contact precautions of children following bOPV vaccination.
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Affiliation(s)
- Odelia Chorin
- The Institute for Rare Diseases, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel-Hashomer, Israel; Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; The Danek Gertner Institute of Human Genetics, Sheba Medical Center, Tel-Hashomer, Israel.
| | | | | | - Sarit Rahmani
- Tel Aviv Department of Health, Ministry of Health, Tel Aviv, Israel
| | - Danit Sofer
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Merav Weil
- Central Virology Laboratory, Public Health Services, Ministry of Health, Chaim Sheba Medical Center, Ramat Gan, Israel
| | - Tamy Shohat
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Ehud Chorin
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Department of Cardiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Diana Tasher
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Pediatric Department and Infectious Disease Unit, Wolfson Medical Center, Holon, Israel
| | - Eli Somekh
- Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Mayanei Hayeshuah Medical Center, Bnei Brak, Israel
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John TJ, Hirschhorn N, Dharmapalan D. Choosing the Right Path toward Polio Eradication. N Engl J Med 2023; 388:1824. [PMID: 37163639 DOI: 10.1056/nejmc2303169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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Kalkowska DA, Badizadegan K, Thompson KM. Outbreak management strategies for cocirculation of multiple poliovirus types. Vaccine 2023:S0264-410X(23)00429-2. [PMID: 37121801 DOI: 10.1016/j.vaccine.2023.04.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/11/2023] [Indexed: 05/02/2023]
Abstract
Prior modeling studies showed that current outbreak management strategies are unlikely to stop outbreaks caused by type 1 wild polioviruses (WPV1) or circulating vaccine-derived polioviruses (cVDPVs) in many areas, and suggested increased risks of outbreaks with cocirculation of more than one type of poliovirus. The surge of type 2 poliovirus transmission that began in 2019 and continues to date, in conjunction with decreases in preventive supplemental immunization activities (SIAs) for poliovirus types 1 and 3, has led to the emergence of several countries with cocirculation of more than one type of poliovirus. Response to these emerging cocirculation events is theoretically straightforward, but the different formulations, types, and inventories of oral poliovirus vaccines (OPVs) available for outbreak response present challenging practical questions. In order to demonstrate the implications of using different vaccine options and outbreak campaign strategies, we applied a transmission model to a hypothetical population with conditions similar to populations currently experiencing outbreaks of cVDPVs of both types 1 and 2. Our results suggest prevention of the largest number of paralytic cases occurs when using (1) trivalent OPV (tOPV) (or coadministering OPV formulations for all three types) until one poliovirus outbreak type dies out, followed by (2) using a type-specific OPV until the remaining poliovirus outbreak type also dies out. Using tOPV first offers a lower overall expected cost, but this option may be limited by the willingness to expose populations to type 2 Sabin OPV strains. For strategies that use type 2 novel OPV (nOPV2) concurrently administered with bivalent OPV (bOPV, containing types 1 and 3 OPV) emerges as a leading option, but questions remain about feasibility, logistics, type-specific take rates, and coadministration costs.
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Kalkowska DA, Wassilak SGF, Wiesen E, F Estivariz C, Burns CC, Badizadegan K, Thompson KM. Complexity of options related to restarting oral poliovirus vaccine (OPV) in national immunization programs after OPV cessation. Gates Open Res 2023; 7:55. [PMID: 37547300 PMCID: PMC10403636 DOI: 10.12688/gatesopenres.14511.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2023] [Indexed: 08/08/2023] Open
Abstract
Background: The polio eradication endgame continues to increase in complexity. With polio cases caused by wild poliovirus type 1 and circulating vaccine-derived polioviruses of all three types (1, 2 and 3) reported in 2022, the number, formulation, and use of poliovirus vaccines poses challenges for national immunization programs and vaccine suppliers. Prior poliovirus transmission modeling of globally-coordinated type-specific cessation of oral poliovirus vaccine (OPV) assumed creation of Sabin monovalent OPV (mOPV) stockpiles for emergencies and explored the potential need to restart OPV if the world reached a specified cumulative threshold number of cases after OPV cessation. Methods: We document the actual experience of type 2 OPV (OPV2) cessation and reconsider prior modeling assumptions related to OPV restart. We develop updated decision trees of national immunization options for poliovirus vaccines considering different possibilities for OPV restart. Results: While OPV restart represented a hypothetical situation for risk management and contingency planning to support the 2013-2018 Global Polio Eradication Initiative (GPEI) Strategic Plan, the actual epidemiological experience since OPV2 cessation raises questions about what, if any, trigger(s) could lead to restarting the use of OPV2 in routine immunization and/or plans for potential future restart of type 1 and 3 OPV after their respective cessation. The emergency use listing of a genetically stabilized novel type 2 OPV (nOPV2) and continued evaluation of nOPV for types 1 and/or 3 add further complexity by increasing the combinations of possible OPV formulations for OPV restart. Conclusions: Expanding on a 2019 discussion of the logistical challenges and implications of restarting OPV, we find a complex structure of the many options and many issues related to OPV restart decisions and policies as of early 2023. We anticipate many challenges for forecasting prospective vaccine supply needs during the polio endgame due to increasing potential combinations of poliovirus vaccine choices.
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Affiliation(s)
| | - Steven GF Wassilak
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Eric Wiesen
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Concepcion F Estivariz
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Cara C Burns
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, USA, Atlanta, GA, USA
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Thompson KM, Kalkowska DA, Badizadegan K. Oral polio vaccine stockpile modeling: insights from recent experience. Expert Rev Vaccines 2023; 22:813-825. [PMID: 37747090 DOI: 10.1080/14760584.2023.2263096] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/21/2023] [Indexed: 09/26/2023]
Abstract
BACKGROUND Achieving polio eradication requires ensuring the delivery of sufficient supplies of the right vaccines to the right places at the right times. Despite large global markets, decades of use, and large quantity purchases of polio vaccines by national immunization programs and the Global Polio Eradication Initiative (GPEI), forecasting demand for the oral poliovirus vaccine (OPV) stockpile remains challenging. RESEARCH DESIGN AND METHODS We review OPV stockpile experience compared to pre-2016 expectations, actual demand, and changes in GPEI policies related to the procurement and use of type 2 OPV vaccines. We use available population and immunization schedule data to explore polio vaccine market segmentation, and its role in polio vaccine demand forecasting. RESULTS We find that substantial challenges remain in forecasting polio vaccine needs, mainly due to (1) deviations in implementation of plans that formed the basis for earlier forecasts, (2) lack of alignment of tactics/objectives among GPEI partners and other key stakeholders, (3) financing, and (4) uncertainty about development and licensure timelines for new polio vaccines and their field performance characteristics. CONCLUSIONS Mismatches between supply and demand over time have led to negative consequences associated with both oversupply and undersupply, as well as excess costs and potentially preventable cases.
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Thompson KM, Kalkowska DA, Badizadegan K. Health economic analysis of vaccine options for the polio eradication endgame: 2022-2036. Expert Rev Vaccines 2022; 21:1667-1674. [PMID: 36154436 PMCID: PMC10116513 DOI: 10.1080/14760584.2022.2128108] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND : Multiple vaccine options are available for polio prevention and risk management. Integrated global risk, economic, and poliovirus transmission modeling provides a tool to explore the dynamics of ending all use of one or more poliovirus vaccines to simplify the polio eradication endgame. RESEARCH DESIGN AND METHODS : With global reported cases of poliomyelitis trending higher since 2016, we apply an integrated global model to simulate prospective vaccine policies and strategies for OPV-using countries starting with initial conditions that correspond to the epidemiological poliovirus transmission situation at the beginning of 2022. RESULTS : Abruptly ending all OPV use in 2023 and relying only on IPV to prevent paralysis with current routine immunization coverage would lead to expected reestablished endemic transmission of poliovirus types 1 and 2, and approximately 150,000 expected cases of poliomyelitis per year. Alternatively, if OPV-using countries restart trivalent OPV (tOPV) use for all immunization activities and end IPV use, the model shows the lowest anticipated annual polio cases and lowest costs. CONCLUSIONS : Poor global risk management and coordination of OPV cessation remain a critical failure mode for the polio endgame, and national and global decision makers face difficult choices due to multiple available polio vaccine options and immunization strategies.
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Xu Y, Liu Y, Wang J, Che X, Du J, Zhang X, Gu W, Zhang X, Jiang W. Cost-effectiveness of various immunization schedules with inactivated Sabin strain polio vaccine in Hangzhou, China. Front Public Health 2022; 10:990042. [PMID: 36211670 PMCID: PMC9545176 DOI: 10.3389/fpubh.2022.990042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/24/2022] [Indexed: 01/26/2023] Open
Abstract
Background It is necessary to select suitable inactivated poliovirus vaccine(IPV) and live, attenuated oral poliovirus vaccine (OPV) sequential immunization programs and configure the corresponding health resources. An economic evaluation was conducted on the sequential procedures of Sabin strain-based IPV (sIPV) and bivalent OPV (bOPV) with different doses to verify whether a cost-effectiveness target can be achieved. This study aimed to evaluate the cost-effectiveness of different sIPV immunization schedules, which would provide convincing evidence to further change the poliovirus vaccine (PV) immunization strategies in China. Methods Five strategies were included in this analysis. Based on Strategy 0(S0), the incremental cost (IC), incremental effect (IE), and incremental cost-effectiveness ratio (ICER) of the four different strategies (S1/S2/S3/S4) were calculated based on the perspective of the society. Seven cost items were included in this study. Results of field investigations and expert consultations were used to calculate these costs. Results The ICs of S1/S2/S3/S4 was Chinese Yuan (CNY) 30.77, 68.58, 103.82, and 219.82 million, respectively. The IE of vaccine-associated paralytic poliomyelitis (IEVAPP) cases of S1/S2/S3/S4 were 0.22, 0.22, 0.22, and 0.11, respectively, while the IE of disability-adjusted life-years (IEDALY) of S1/S2/S3/S4 were 8.98, 8.98, 8.98, and 4.49, respectively. The ICERVAPP of S1/S2/S3/S4 gradually increased to CNY 13.99, 31.17, 47.19, and 199.83 million/VAPP, respectively. The ICERDALY of S1/S2/S3/S4 also gradually increased to CNY 0.34, 0.76, 1.16, and 4.90 million/DALY, respectively. Conclusion ICERVAPP and ICERDALY were substantially higher for S3 (four-sIPV) and S4 (replacement of self-funded sIPV based on one-sIPV-three-bOPV). Two-sIPV-two-bOPV had a cost-effectiveness advantage, whereas S2/S3/S4 had no cost-effectiveness advantage.
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Al-Qassimi MA, Al Amad M, Anam L, Almoayed K, Al-Dar A, Ezzadeen F. Circulating vaccine derived polio virus type 1 outbreak, Saadah governorate, Yemen, 2020. BMC Infect Dis 2022; 22:414. [PMID: 35488227 PMCID: PMC9052627 DOI: 10.1186/s12879-022-07397-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 04/18/2022] [Indexed: 11/19/2022] Open
Abstract
Background Yemen has faced one of the worst humanitarian crises in the world since the start of the war in 2015. In 2020; 30 Vaccine Derived Polio Virus type 1 (VDPV1) isolates were detected in Saadah governorate. The aims are to characterize the outbreak and address the gaps predisposing the emergence and circulation of VDPV1 in Saadah governorate, Yemen. Method A retrospective descriptive study of confirmed cases of VDPV1 between January and December 2020 was performed. Surveillance staff collected data from patient cases, contacts, as well as stool specimens that shipped to WHO accredited polio labs. Data of population immunity was also reviewed. The difference in days between the date of sample collection, shipment, and receiving lab result was used to calculate the average of delayed days for lab confirmation. Results From January to December 2020, a total of 114 cases of acute flaccid paralysis (AFP) were reported from 87% (13/15) districts, and cVDPV1 was confirmed among 26% (30) AFP cases. 75% (21) were < 5 years, 73% (20) had zero doses of Oral Polio Vaccine (OPV). The first confirmed case (3%) was from Saadah city, with paralysis onset at the end of January 2020 followed by 5 cases (17%) in March from another four districts, 8 cases (27%) in April, and 13 (43%) up to December 2020 were from the same five districts in addition to 3 (10%) form three new districts. The lab confirmation was received after an average of 126 days (71–196) from sample collection. The isolates differ from the Sabin 1 type by 17- 30 VP1 nucleotides (nt) and were linked to VDPV1 with 13 (nt) divergence that isolated in July 2020 from stool specimens collected before one year from contacts of an inadequate AFP case reported from Sahar district. Conclusion The new emerging VDPV1 was retrospectively confirmed after one year of sample collection from Sahar district. Delayed lab confirmation, as well as the response and low immunization profile of children against polio, were the main predisposing factors for cVDPV1 outbreak. This outbreak highlights the need to maintain regular biweekly shipments to referral polio labs in the short-term, and the exploration of other options in the longer-term to enable the Yemen National Lab to fully process national samples itself. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07397-0.
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Affiliation(s)
| | - Mohammed Al Amad
- Field Epidemiology Training Program, Yemen Ministry of Public Health and Population, Sana'a, Yemen
| | - Labiba Anam
- Field Epidemiology Training Program, Yemen Ministry of Public Health and Population, Sana'a, Yemen
| | - Khaled Almoayed
- General Directorate for Diseases Control and Surveillance, Yemen Ministry of Public Health and Population, Sana'a, Yemen
| | - Ahmed Al-Dar
- National Polio Surveillance, Yemen Ministry of Public Health and Population, Sana'a, Yemen
| | - Faten Ezzadeen
- National Polio Surveillance, Yemen Ministry of Public Health and Population, Sana'a, Yemen
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Badizadegan K, Kalkowska DA, Thompson KM. Polio by the Numbers - A Global Perspective. J Infect Dis 2022; 226:1309-1318. [PMID: 35415741 PMCID: PMC9556648 DOI: 10.1093/infdis/jiac130] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/05/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Investments in national immunization programs and the Global Polio Eradication Initiative (GPEI) have resulted in substantial reductions in paralytic polio worldwide. However, cases prevented because of investments in immunization programs and GPEI remain incompletely characterized. METHODS Using a global model that integrates polio transmission, immunity, and vaccine dynamics, we provide estimates of polio incidence and numbers of paralytic cases prevented. We compare the results with reported cases and estimates historically published by the World Health Organization. RESULTS We estimate that the existence and use of polio vaccines prevented 5 million cases of paralytic polio between 1960-1987 and 24 million cases worldwide for 1988-2021 compared to a counterfactual world with no polio vaccines. Since the 1988 resolution to eradicate polio, our estimates suggest GPEI prevented 2.5 to 6 million cases of paralytic polio compared to counterfactual worlds without GPEI that assume different levels of intensity of polio vaccine use in routine immunization programs. DISCUSSION Analysis of historical cases provides important context for understanding and communicating the benefits of investments made in polio eradication. Prospective studies will need to explore the expected benefits of future investments, the outcomes of which will depend on whether and when polio is globally eradicated.
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Chumakov K, Ehrenfeld E, Agol VI, Wimmer E. Polio eradication at the crossroads. LANCET GLOBAL HEALTH 2021; 9:e1172-e1175. [PMID: 34118192 DOI: 10.1016/s2214-109x(21)00205-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 04/09/2021] [Indexed: 12/23/2022]
Abstract
The Global Polio Eradication Initiative, launched in 1988 with anticipated completion by 2000, has yet to reach its ultimate goal. The recent surge of polio cases urgently calls for a reassessment of the programme's current strategy and a new design for the way forward. We propose that the sustainable protection of the world population against paralytic polio cannot be achieved simply by stopping the circulation of poliovirus but must also include maintaining high rates of population immunity indefinitely, which can be created and maintained by implementing global immunisation programmes with improved poliovirus vaccines that create comprehensive immunity without spawning new virulent viruses. The proposed new strategic goal of eradicating the disease rather than the virus would lead to a sustainable eradication of poliomyelitis while simultaneously promoting immunisation against other vaccine-preventable diseases.
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Affiliation(s)
- Konstantin Chumakov
- Office of Vaccines Research and Review, Food and Drug Administration, Global Virus Network Center of Excellence, Silver Spring, MD, USA.
| | - Ellie Ehrenfeld
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Vadim I Agol
- MP Chumakov Center for Research and Development of Immunobiological Products, Moscow, Russia; AN Belozersky Institute of Physical-Chemical Biology, MV Lomonosov Moscow State University, Moscow, Russia
| | - Eckard Wimmer
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, USA
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Zhao T, Li J, Shi H, Ye H, Ma R, Fu Y, Liu X, Li G, Yang X, Zhao Z, Yang J. Reduced mucosal immunity to poliovirus after cessation of trivalent oral polio vaccine. Hum Vaccin Immunother 2021; 17:2560-2567. [PMID: 33848232 PMCID: PMC8475588 DOI: 10.1080/21645515.2021.1911213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The switch from using only trivalent oral polio vaccine (tOPV) to sequential schedules combining inactivated poliovirus vaccine (IPV) and bivalent oral polio vaccine (bOPV) for polio vaccination will cause changes to mucosal immunity against polio in infants, which plays an important role in preventing the poliovirus spread. Here, we analyzed mucosal immunity against poliovirus in the intestine during different sequential vaccination schedules. We conducted clinical trials in Guangxi Province, China on 1,200 2-month-old infants who were randomly assigned to one of three vaccination schedule groups: IPV-bOPV-bOPV, IPV-IPV-tOPV, and IPV-IPV-bOPV, with vaccine doses administered at 8, 12, and 16 weeks of age. Stool samples were collected from 10% of participants in each group before administration of the second vaccine doses and at 1, 2, and 4 weeks after the administrations of the second and third vaccine doses. Immunoglobulin A (IgA) in the stool samples was measured to analyze the mucosal immune response in the intestine. Because of the absence of poliovirus type 2 in bOPV, the vaccination schedule of IPV-IPV-bOPV did not sufficiently raise intestinal mucosal immunity against poliovirus type 2, although some cross-immunity was seen. The level of intestinal mucosal immunity was related to shedding status; shedders could produce intestinal mucosa IgA more quickly. The intestinal mucosal immunity level was not related to serum neutralizing antibody level. In the combined sequential vaccination schedule of IPV and bOPV, the risk of circulating vaccine-derived poliovirus type 2 (cVDPV2) may be increased owing to insufficient intestinal mucosal immunity against poliovirus type 2.
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Affiliation(s)
- Ting Zhao
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Jing Li
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Hongyuan Shi
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Hui Ye
- Hangzhou Women's Hospital Hangzhou Maternity and Child Health Care Hospital, Hangzhou, China
| | - Rufei Ma
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Yuting Fu
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Xiaochang Liu
- Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Guoliang Li
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Xiaolei Yang
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Zhimei Zhao
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
| | - Jingsi Yang
- Yunnan Key Laboratory of Vaccine Research & Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming, China
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Kalkowska DA, Pallansch MA, Wilkinson A, Bandyopadhyay AS, Konopka-Anstadt JL, Burns CC, Oberste MS, Wassilak SGF, Badizadegan K, Thompson KM. Updated Characterization of Outbreak Response Strategies for 2019-2029: Impacts of Using a Novel Type 2 Oral Poliovirus Vaccine Strain. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2021; 41:329-348. [PMID: 33174263 PMCID: PMC7887065 DOI: 10.1111/risa.13622] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/08/2020] [Accepted: 10/16/2020] [Indexed: 05/06/2023]
Abstract
Delays in achieving the global eradication of wild poliovirus transmission continue to postpone subsequent cessation of all oral poliovirus vaccine (OPV) use. Countries must stop OPV use to end all cases of poliomyelitis, including vaccine-associated paralytic polio (VAPP) and cases caused by vaccine-derived polioviruses (VDPVs). The Global Polio Eradication Initiative (GPEI) coordinated global cessation of all type 2 OPV (OPV2) use in routine immunization in 2016 but did not successfully end the transmission of type 2 VDPVs (VDPV2s), and consequently continues to use type 2 OPV (OPV2) for outbreak response activities. Using an updated global poliovirus transmission and OPV evolution model, we characterize outbreak response options for 2019-2029 related to responding to VDPV2 outbreaks with a genetically stabilized novel OPV (nOPV2) strain or with the currently licensed monovalent OPV2 (mOPV2). Given uncertainties about the properties of nOPV2, we model different assumptions that appear consistent with the evidence on nOPV2 to date. Using nOPV2 to respond to detected cases may reduce the expected VDPV and VAPP cases and the risk of needing to restart OPV2 use in routine immunization compared to mOPV2 use for outbreak response. The actual properties, availability, and use of nOPV2 will determine its effects on type 2 poliovirus transmission in populations. Even with optimal nOPV2 performance, countries and the GPEI would still likely need to restart OPV2 use in routine immunization in OPV-using countries if operational improvements in outbreak response to stop the transmission of cVDPV2s are not implemented effectively.
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Affiliation(s)
| | - Mark A. Pallansch
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Amanda Wilkinson
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Jennifer L. Konopka-Anstadt
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Cara C. Burns
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - M. Steven Oberste
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Steven G. F. Wassilak
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | | | - Kimberly M. Thompson
- Kid Risk, Inc., Orlando, FL, USA
- Correspondence to: Kimberly Thompson, Kid Risk, Inc., 7512 Dr. Phillips Blvd. #50-523, Orlando, FL 32819, USA,
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Kalkowska DA, Pallansch MA, F. Wassilak SG, Cochi SL, Thompson KM. Global Transmission of Live Polioviruses: Updated Dynamic Modeling of the Polio Endgame. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2021; 41:248-265. [PMID: 31960533 PMCID: PMC7787008 DOI: 10.1111/risa.13447] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/30/2019] [Accepted: 12/02/2019] [Indexed: 05/05/2023]
Abstract
Nearly 20 years after the year 2000 target for global wild poliovirus (WPV) eradication, live polioviruses continue to circulate with all three serotypes posing challenges for the polio endgame. We updated a global differential equation-based poliovirus transmission and stochastic risk model to include programmatic and epidemiological experience through January 2020. We used the model to explore the likely dynamics of poliovirus transmission for 2019-2023, which coincides with a new Global Polio Eradication Initiative Strategic Plan. The model stratifies the global population into 72 blocks, each containing 10 subpopulations of approximately 10.7 million people. Exported viruses go into subpopulations within the same block and within groups of blocks that represent large preferentially mixing geographical areas (e.g., continents). We assign representative World Bank income levels to the blocks along with polio immunization and transmission assumptions, which capture some of the heterogeneity across countries while still focusing on global poliovirus transmission dynamics. We also updated estimates of reintroduction risks using available evidence. The updated model characterizes transmission dynamics and resulting polio cases consistent with the evidence through 2019. Based on recent epidemiological experience and prospective immunization assumptions for the 2019-2023 Strategic Plan, the updated model does not show successful eradication of serotype 1 WPV by 2023 or successful cessation of oral poliovirus vaccine serotype 2-related viruses.
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Affiliation(s)
| | - Mark A. Pallansch
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Steven G. F. Wassilak
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stephen L. Cochi
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Thompson KM, Kalkowska DA. Potential Future Use, Costs, and Value of Poliovirus Vaccines. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2021; 41:349-363. [PMID: 32645244 PMCID: PMC7984393 DOI: 10.1111/risa.13557] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/22/2020] [Indexed: 05/06/2023]
Abstract
Countries face different poliovirus risks, which imply different benefits associated with continued and future use of oral poliovirus vaccine (OPV) and/or inactivated poliovirus vaccine (IPV). With the Global Polio Eradication Initiative (GPEI) continuing to extend its timeline for ending the transmission of all wild polioviruses and to introduce new poliovirus vaccines, the polio vaccine supply chain continues to expand in complexity. The increased complexity leads to significant uncertainty about supply and costs. Notably, the strategy of phased OPV cessation of all three serotypes to stop all future incidence of poliomyelitis depends on successfully stopping the transmission of all wild polioviruses. Countries also face challenges associated with responding to any outbreaks that occur after OPV cessation, because stopping transmission of such outbreaks requires reintroducing the use of the stopped OPV in most countries. National immunization program leaders will likely consider differences in their risks and willingness-to-pay for risk reduction as they evaluate their investments in current and future polio vaccination. Information about the costs and benefits of future poliovirus vaccines, and discussion of the complex situation that currently exists, should prove useful to national, regional, and global decisionmakers and support health economic modeling. Delays in achieving polio eradication combined with increasing costs of poliovirus vaccines continue to increase financial risks for the GPEI.
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Kalkowska DA, Thompson KM. Health and Economic Outcomes Associated with Polio Vaccine Policy Options: 2019-2029. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2021; 41:364-375. [PMID: 33590519 PMCID: PMC7895457 DOI: 10.1111/risa.13664] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/04/2020] [Indexed: 05/08/2023]
Abstract
The polio endgame remains complicated, with many questions about future polio vaccines and national immunization policies. We simulated possible future poliovirus vaccine routine immunization policies for countries stratified by World Bank Income Levels and estimated the expected costs and cases using an updated integrated dynamic poliovirus transmission, stochastic risk, and economic model. We consider two reference cases scenarios: one that achieves the eradication of all wild polioviruses (WPVs) by 2023 and one in which serotype 1 WPV (WPV1) transmission continues. The results show that the addition of inactivated poliovirus vaccine (IPV) to routine immunization in all countries substantially increased the expected costs of the polio endgame, without substantially increasing its expected health or economic benefits. Adding a second dose of IPV to the routine immunization schedules of countries that currently include a single IPV dose further increases costs and does not appear economically justified in the reference case that does not stop WPV transmission. For the reference case that includes all WPV eradication, adding a second IPV dose at the time of successful oral poliovirus vaccine (OPV) cessation represents a cost-effective option. The risks and costs of needing to restart OPV use change the economics of the polio endgame, although the time horizon used for modeling impacts the overall economic results. National health leaders will want to consider the expected health and economic net benefits of their national polio vaccine strategies recognizing that preferred strategies may differ.
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Din M, Ali H, Khan M, Waris A, Ullah S, Kashif M, Rahman S, Ali M. Impact of COVID-19 on polio vaccination in Pakistan: a concise overview. Rev Med Virol 2020; 31:e2190. [PMID: 33176028 DOI: 10.1002/rmv.2190] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 11/07/2022]
Abstract
The pandemic of coronavirus disease 2019 (COVID-19) has disrupted immunization programs around the globe, potentially increasing life-threatening vaccine-preventable diseases. Pakistan and Afghanistan are the only countries, which are still struggling to eradicate wild poliovirus. All vaccination campaigns in Pakistan were suspended in April due to the COVID-19 outbreak, leading 40 million children to miss out on polio vaccination. Like the climate crisis, the COVID-19 pandemic could be regarded as a child-rights crisis because it could have life-threatening impact over children, who need immunization, now and in the long-term. Delays in polio vaccination programs might not have immediate impact but, in the long-term, the increase in polio cases in Pakistan could result in the global export of infections. Therefore, healthcare authorities must intensify their efforts to track and vaccinate unvaccinated children in countries like Pakistan and Afghanistan. Polio vaccination campaigns need to resume immediately, so we suggest applying social distancing measures along with standard operating procedure to flatten the transmission curve of COVID-19. Furthermore, the concurrent emergence of cVDPV2 means that tOPV should temporarily be used for primary immunization. In the current review, we have discussed delays in polio vaccination, surveillance of polio viruses, reported cases in Pakistan along with recommendations to overcome interrupted immunization.
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Affiliation(s)
- Misbahud Din
- Department of Biotechnology, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
| | - Hammad Ali
- Department of Biotechnology, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
| | - Mudassir Khan
- Department of Healthcare Biotechnology, Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Science and Technology (NUST), Islamabad, Pakistan
| | - Abdul Waris
- Department of Biotechnology, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
| | - Sana Ullah
- Department of Biotechnology, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
| | - Muhammad Kashif
- Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Sidra Rahman
- Department of Biotechnology, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
| | - Muhammad Ali
- Department of Biotechnology, Quaid-i-Azam University Islamabad, Islamabad, Pakistan
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Thompson KM, Kalkowska DA. Review of poliovirus modeling performed from 2000 to 2019 to support global polio eradication. Expert Rev Vaccines 2020; 19:661-686. [PMID: 32741232 PMCID: PMC7497282 DOI: 10.1080/14760584.2020.1791093] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/22/2020] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Over the last 20 years (2000-2019) the partners of the Global Polio Eradication Initiative (GPEI) invested in the development and application of mathematical models of poliovirus transmission as well as economics, policy, and risk analyses of polio endgame risk management options, including policies related to poliovirus vaccine use during the polio endgame. AREAS COVERED This review provides a historical record of the polio studies published by the three modeling groups that primarily performed the bulk of this work. This review also systematically evaluates the polio transmission and health economic modeling papers published in English in peer-reviewed journals from 2000 to 2019, highlights differences in approaches and methods, shows the geographic coverage of the transmission modeling performed, identified common themes, and discusses instances of similar or conflicting insights or recommendations. EXPERT OPINION Polio modeling performed during the last 20 years substantially impacted polio vaccine choices, immunization policies, and the polio eradication pathway. As the polio endgame continues, national preferences for polio vaccine formulations and immunization strategies will likely continue to change. Future modeling will likely provide important insights about their cost-effectiveness and their relative benefits with respect to controlling polio and potentially achieving and maintaining eradication.
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Kalkowska DA, Pallansch MA, Thompson KM. Updated modelling of the prevalence of immunodeficiency-associated long-term vaccine-derived poliovirus (iVDPV) excreters. Epidemiol Infect 2019; 147:e295. [PMID: 31647050 PMCID: PMC6813650 DOI: 10.1017/s095026881900181x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/16/2019] [Accepted: 10/03/2019] [Indexed: 12/31/2022] Open
Abstract
Conditions and evidence continue to evolve related to the prediction of the prevalence of immunodeficiency-associated long-term vaccine-derived poliovirus (iVDPV) excreters, which affect assumptions related to forecasting risks and evaluating potential risk management options. Multiple recent reviews provided information about individual iVDPV excreters, but inconsistencies among the reviews raise some challenges. This analysis revisits the available evidence related to iVDPV excreters and provides updated model estimates that can support future risk management decisions. The results suggest that the prevalence of iVDPV excreters remains highly uncertain and variable, but generally confirms the importance of managing the risks associated with iVDPV excreters throughout the polio endgame in the context of successful cessation of all oral poliovirus vaccine use.
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Affiliation(s)
| | - M. A. Pallansch
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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21
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Kalkowska DA, Duintjer Tebbens RJ, Pallansch MA, Thompson KM. Modeling Undetected Live Poliovirus Circulation After Apparent Interruption of Transmission: Pakistan and Afghanistan. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2019; 39:402-413. [PMID: 30296340 PMCID: PMC7842182 DOI: 10.1111/risa.13214] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Since most poliovirus infections occur with no paralytic symptoms, the possibility of silent circulation complicates the confirmation of the end of poliovirus transmission. Based on empirical field experience and theoretical modeling results, the Global Polio Eradication Initiative identified three years without observing paralytic cases from wild polioviruses with good acute flaccid paralysis surveillance as an indication of sufficient confidence that poliovirus circulation stopped. The complexities of real populations and the imperfect nature of real surveillance systems subsequently demonstrated the importance of specific modeling for areas at high risk of undetected circulation, resulting in varying periods of time required to obtain the same level of confidence about no undetected circulation. Using a poliovirus transmission model that accounts for variability in transmissibility and neurovirulence for different poliovirus serotypes and characterizes country-specific factors (e.g., vaccination and surveillance activities, demographics) related to wild and vaccine-derived poliovirus transmission in Pakistan and Afghanistan, we consider the probability of undetected poliovirus circulation for those countries once apparent die-out occurs (i.e., in the absence of any epidemiological signals). We find that gaps in poliovirus surveillance or reaching elimination with borderline sufficient population immunity could significantly increase the time to reach high confidence about interruption of live poliovirus transmission, such that the path taken to achieve and maintain poliovirus elimination matters. Pakistan and Afghanistan will need to sustain high-quality surveillance for polioviruses after apparent interruption of transmission and recognize that as efforts to identify cases or circulating live polioviruses decrease, the risks of undetected circulation increase and significantly delay the global polio endgame.
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Affiliation(s)
| | | | - Mark A Pallansch
- Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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22
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Duintjer Tebbens RJ, Thompson KM. Evaluation of Proactive and Reactive Strategies for Polio Eradication Activities in Pakistan and Afghanistan. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2019; 39:389-401. [PMID: 30239026 PMCID: PMC7857157 DOI: 10.1111/risa.13194] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 05/21/2023]
Abstract
Only Pakistan and Afghanistan reported any polio cases caused by serotype 1 wild polioviruses (WPV1s) in 2017. With the dwindling cases in both countries and pressure to finish eradication with the least possible resources, a danger exists of inappropriate prioritization of efforts between the two countries and insufficient investment in the two countries to finish the job. We used an existing differential-equation-based poliovirus transmission and oral poliovirus (OPV) evolution model to simulate a proactive strategy to stop transmission, and different hypothetical reactive strategies that adapt the quality of supplemental immunization activities (SIAs) in response to observed polio cases in Pakistan and Afghanistan. To account for the delay in perception and adaptation, we related the coverage of the SIAs in high-risk, undervaccinated subpopulations to the perceived (i.e., smoothed) polio incidence. Continuation of the current frequency and quality of SIAs remains insufficient to eradicate WPV1 in Pakistan and Afghanistan. Proactive strategies that significantly improve and sustain SIA quality lead to WPV1 eradication and the prevention of circulating vaccine-derived poliovirus (cVDPV) outbreaks. Reactive vaccination efforts that adapt moderately quickly and independently to changes in polio incidence in each country may succeed in WPV1 interruption after several cycles of outbreaks, or may interrupt WPV1 transmission in one country but subsequently import WPV1 from the other country or enable the emergence of cVDPV outbreaks. Reactive vaccination efforts that adapt independently and either more rapidly or more slowly to changes in polio incidence in each country may similarly fail to interrupt WPV1 transmission and result in oscillations of the incidence. Reactive strategies that divert resources to the country of highest priority may lead to alternating large outbreaks. Achieving WPV1 eradication and subsequent successful OPV cessation in Pakistan and Afghanistan requires proactive and sustained efforts to improve vaccination intensity in under-vaccinated subpopulations while maintaining high population immunity elsewhere.
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Pan WK, Seidman JC, Ali A, Hoest C, Mason C, Mondal D, Knobler SL, Bessong P. Oral polio vaccine response in the MAL-ED birth cohort study: Considerations for polio eradication strategies. Vaccine 2018; 37:352-365. [PMID: 30442479 PMCID: PMC6325791 DOI: 10.1016/j.vaccine.2018.05.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 11/28/2022]
Abstract
Background Immunization programs have leveraged decades of research to maximize oral polio vaccine (OPV) response. Moving toward global poliovirus eradication, the WHO recommended phased OPV-to-IPV replacement on schedules in 2012. Using the MAL-ED prospective birth cohort data, we evaluated the influence of early life exposures impacting OPV immunization by measuring OPV response for serotypes 1 and 3. Methods Polio neutralizing antibody assays were conducted at 7 and 15 months of age for serotypes 1 and 3. Analyses were conducted on children receiving ≥3 OPV doses (n = 1449). History of vaccination, feeding patterns, physical growth, home environment, diarrhea, enteropathogen detection, and gut inflammation were examined as risk factors for non-response [Log2(titer) < 3] and Log2(titer) by serotype using multivariate regression. Findings Serotype 1 seroconversion was significantly higher than serotype 3 (96.6% vs. 89.6%, 15 months). Model results indicate serotypes 1 and 3 failure was minimized following four and six OPV doses, respectively; however, enteropathogen detection and poor socioeconomic conditions attenuated response in both serotypes. At three months of age, bacterial detection in stool reduced serotype 1 and 3 Log2 titers by 0.34 (95% CI 0.14–0.54) and 0.53 (95% CI 0.29–0.77), respectively, and increased odds of serotype 3 failure by 3.0 (95% CI 1.6–5.8). Our socioeconomic index, consisting of Water, Assets, Maternal education, and Income (WAMI), was associated with a 0.79 (95% CI 0.15–1.43) and 1.23 (95% CI 0.34–2.12) higher serotype 1 and 3 Log2 titer, respectively, and a 0.04 (95% CI 0.002–0.40) lower odds of serotype 3 failure. Introduction of solids, transferrin receptor, and underweight were differentially associated with serotype response. Other factors, including diarrheal frequency and breastfeeding practices, were not associated with OPV response. Interpretation Under real-world conditions, improved vaccination coverage and socio-environmental conditions, and reducing early life bacterial exposures are key to improving OPV response and should inform polio eradication strategies.
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Affiliation(s)
- William K Pan
- Duke Global Health Institute, Duke University, Trent Hall, 310 Trent Drive, Durham, NC 27710, USA.
| | - Jessica C Seidman
- Fogarty International Center/National Institutes of Health, Bethesda, MD, USA
| | - Asad Ali
- Aga Khan University, Karachi, Pakistan
| | - Christel Hoest
- Fogarty International Center/National Institutes of Health, Bethesda, MD, USA
| | - Carl Mason
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | - Stacey L Knobler
- Fogarty International Center/National Institutes of Health, Bethesda, MD, USA
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Duintjer Tebbens RJ, Kalkowsa DA, Thompson KM. Poliovirus containment risks and their management. Future Virol 2018; 13:617-628. [PMID: 33598044 DOI: 10.2217/fvl-2018-0079] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aim Assess risks related to breaches of poliovirus containment. Method Using a dynamic transmission model, we explore the variability among different populations in the vulnerability to poliovirus containment breaches as population immunity to transmission declines after oral poliovirus vaccine (OPV) cessation. Results Although using OPV instead of wild poliovirus (WPV) seed strains for inactivated poliovirus vaccine (IPV) production offers some expected risk reintroduction of live polioviruses from IPV manufacturing facilities, OPV seed strain releases may become a significant threat within 5-10 years of OPV cessation in areas most conducive to fecal-oral poliovirus transmission, regardless of IPV use. Conclusions Efforts to quantify the risks demonstrate the challenges associated with understanding and managing relatively low-probability and high-consequence containment failure events.
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25
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Duintjer Tebbens RJ, Thompson KM. Polio endgame risks and the possibility of restarting the use of oral poliovirus vaccine. Expert Rev Vaccines 2018; 17:739-751. [PMID: 30056767 PMCID: PMC6168953 DOI: 10.1080/14760584.2018.1506333] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/26/2018] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Ending all cases of poliomyelitis requires successful cessation of all oral poliovirus vaccine (OPV), but the Global Polio Eradication Initiative (GPEI) partners should consider the possibility of an OPV restart. AREAS COVERED We review the risks of continued live poliovirus transmission after OPV cessation and characterize events that led to OPV restart in a global model that focused on identifying optimal strategies for OPV cessation and the polio endgame. Numerous different types of events that occurred since the globally coordinated cessation of serotype 2-containing OPV in 2016 highlight the possibility of continued outbreaks after homotypic OPV cessation. Modeling suggests a high risk of uncontrolled outbreaks once more than around 5,000 homotypic polio cases occur after cessation of an OPV serotype, at which point restarting OPV would become necessary to protect most populations. Current efforts to sunset the GPEI and transition its responsibilities to national governments poses risks that may limit the ability to implement management strategies needed to minimize the probability of an OPV restart. EXPERT COMMENTARY OPV restart remains a real possibility, but risk management choices made by the GPEI partners and national governments can reduce the risks of this low-probability but high-consequence event.
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26
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Duintjer Tebbens RJ, Pallansch MA, Cochi SL, Ehrhardt D, Farag N, Hadler S, Hampton LM, Martinez M, Wassilak SG, Thompson KM. Modeling Poliovirus Transmission in Pakistan and Afghanistan to Inform Vaccination Strategies in Undervaccinated Subpopulations. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2018; 38:1701-1717. [PMID: 29314143 PMCID: PMC7879700 DOI: 10.1111/risa.12962] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 11/18/2017] [Accepted: 11/22/2017] [Indexed: 05/11/2023]
Abstract
Due to security, access, and programmatic challenges in areas of Pakistan and Afghanistan, both countries continue to sustain indigenous wild poliovirus (WPV) transmission and threaten the success of global polio eradication and oral poliovirus vaccine (OPV) cessation. We fitted an existing differential-equation-based poliovirus transmission and OPV evolution model to Pakistan and Afghanistan using four subpopulations to characterize the well-vaccinated and undervaccinated subpopulations in each country. We explored retrospective and prospective scenarios for using inactivated poliovirus vaccine (IPV) in routine immunization or supplemental immunization activities (SIAs). The undervaccinated subpopulations sustain the circulation of serotype 1 WPV and serotype 2 circulating vaccine-derived poliovirus. We find a moderate impact of past IPV use on polio incidence and population immunity to transmission mainly due to (1) the boosting effect of IPV for individuals with preexisting immunity from a live poliovirus infection and (2) the effect of IPV-only on oropharyngeal transmission for individuals without preexisting immunity from a live poliovirus infection. Future IPV use may similarly yield moderate benefits, particularly if access to undervaccinated subpopulations dramatically improves. However, OPV provides a much greater impact on transmission and the incremental benefit of IPV in addition to OPV remains limited. This study suggests that despite the moderate effect of using IPV in SIAs, using OPV in SIAs remains the most effective means to stop transmission, while limited IPV resources should prioritize IPV use in routine immunization.
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Affiliation(s)
| | - Mark A. Pallansch
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stephen L. Cochi
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Derek Ehrhardt
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Noha Farag
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stephen Hadler
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Lee M. Hampton
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Maureen Martinez
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Steve G.F Wassilak
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Kalkowska DA, Duintjer Tebbens RJ, Thompson KM. Another look at silent circulation of poliovirus in small populations. Infect Dis Model 2018; 3:107-117. [PMID: 30839913 PMCID: PMC6326228 DOI: 10.1016/j.idm.2018.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/13/2018] [Accepted: 06/01/2018] [Indexed: 11/26/2022] Open
Abstract
Background Silent circulation of polioviruses complicates the polio endgame and motivates analyses that explore the probability of undetected circulation for different scenarios. A recent analysis suggested a relatively high probability of unusually long silent circulation of polioviruses in small populations (defined as 10,000 people or smaller). Methods We independently replicated the simple, hypothetical model by Vallejo et al. (2017) and repeated their analyses to explore the model behavior, interpretation of the results, and implications of simplifying assumptions. Results We found a similar trend of increasing times between detected cases with increasing basic reproduction number (R0) and population size. However, we found substantially lower estimates of the probability of at least 3 years between successive polio cases than they reported, which appear more consistent with the prior literature. While small and isolated populations may sustain prolonged silent circulation, our reanalysis suggests that the existing rule of thumb of less than a 5% chance of 3 or more years of undetected circulation with perfect surveillance holds for most conditions of the model used by Vallejo et al. and most realistic conditions. Conclusions Avoiding gaps in surveillance remains critical to declaring wild poliovirus elimination with high confidence as soon as possible after the last detected poliovirus, but concern about transmission in small populations with adequate surveillance should not significantly change the criteria for the certification of wild polioviruses.
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Key Words
- AFP, acute flaccid paralysis
- CFP, case-free period
- CNC, confidence about no circulation
- CNCx%, time when the confidence about no circulation exceeds x%
- DEFP, detected-event-free period
- OPV, oral poliovirus vaccine
- POE, Probability of eradication
- Polio
- Silent circulation
- Small populations
- Stochastic modeling
- TBC, time between detected cases
- TUC, time of undetected circulation after the last detected-event
- TUCx%, xth percentile of the TUC
- WPV, wild poliovirus
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Affiliation(s)
| | | | - Kimberly M. Thompson
- Corresponding author. Kid Risk, Inc., 605 N. High St. #253, Columbus, OH 43215, USA.
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Tebbens RJD, Thompson KM. Using integrated modeling to support the global eradication of vaccine-preventable diseases. SYSTEM DYNAMICS REVIEW 2018; 34:78-120. [PMID: 34552305 PMCID: PMC8455164 DOI: 10.1002/sdr.1589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 02/11/2018] [Indexed: 05/17/2023]
Abstract
The long-term management of global disease eradication initiatives involves numerous inherently dynamic processes, health and economic trade-offs, significant uncertainty and variability, rare events with big consequences, complex and inter-related decisions, and a requirement for cooperation among a large number of stakeholders. Over the course of more than 16 years of collaborative modeling efforts to support the Global Polio Eradication Initiative, we developed increasingly complex integrated system dynamics models that combined numerous analytical approaches, including differential equation-based modeling, risk and decision analysis, discrete-event and individual-based simulation, probabilistic uncertainty and sensitivity analysis, health economics, and optimization. We discuss the central role of systems thinking and system dynamics in the overall effort and the value of integrating different modeling approaches to appropriately address the trade-offs involved in some of the policy questions. We discuss practical challenges of integrating different analytical tools and we provide our perspective on the future of integrated modeling.
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Famulare M, Selinger C, McCarthy KA, Eckhoff PA, Chabot-Couture G. Assessing the stability of polio eradication after the withdrawal of oral polio vaccine. PLoS Biol 2018; 16:e2002468. [PMID: 29702638 PMCID: PMC5942853 DOI: 10.1371/journal.pbio.2002468] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/09/2018] [Accepted: 03/28/2018] [Indexed: 11/18/2022] Open
Abstract
The oral polio vaccine (OPV) contains live-attenuated polioviruses that induce immunity by causing low virulence infections in vaccine recipients and their close contacts. Widespread immunization with OPV has reduced the annual global burden of paralytic poliomyelitis by a factor of 10,000 or more and has driven wild poliovirus (WPV) to the brink of eradication. However, in instances that have so far been rare, OPV can paralyze vaccine recipients and generate vaccine-derived polio outbreaks. To complete polio eradication, OPV use should eventually cease, but doing so will leave a growing population fully susceptible to infection. If poliovirus is reintroduced after OPV cessation, under what conditions will OPV vaccination be required to interrupt transmission? Can conditions exist in which OPV and WPV reintroduction present similar risks of transmission? To answer these questions, we built a multi-scale mathematical model of infection and transmission calibrated to data from clinical trials and field epidemiology studies. At the within-host level, the model describes the effects of vaccination and waning immunity on shedding and oral susceptibility to infection. At the between-host level, the model emulates the interaction of shedding and oral susceptibility with sanitation and person-to-person contact patterns to determine the transmission rate in communities. Our results show that inactivated polio vaccine (IPV) is sufficient to prevent outbreaks in low transmission rate settings and that OPV can be reintroduced and withdrawn as needed in moderate transmission rate settings. However, in high transmission rate settings, the conditions that support vaccine-derived outbreaks have only been rare because population immunity has been high. Absent population immunity, the Sabin strains from OPV will be nearly as capable of causing outbreaks as WPV. If post-cessation outbreak responses are followed by new vaccine-derived outbreaks, strategies to restore population immunity will be required to ensure the stability of polio eradication. Oral polio vaccine (OPV) has played an essential role in the elimination of wild poliovirus (WPV). OPV contains attenuated (weakened) yet transmissible viruses that can spread from person to person. In its attenuated form, this spread is beneficial as it generates population immunity. However, the attenuation of OPV is unstable and it can, in rare instances, revert to a virulent form and cause vaccine-derived outbreaks of paralytic poliomyelitis. Thus, OPV is both a vaccine and a source of poliovirus, and for complete eradication, its use in vaccination must be ended. After OPV is no longer used in routine immunization, as with the cessation of type 2 OPV in 2016, population immunity to polioviruses will decline. A key question is how this loss of population immunity will affect the potential of OPV viruses to spread within and across communities. To address this, we examined the roles of immunity, sanitation, and social contact in limiting OPV transmission. Our results derive from an extensive review and synthesis of vaccine trial data and community epidemiological studies. Shedding, oral susceptibility to infection, and transmission data are analyzed to systematically explain and model observations of WPV and OPV circulation. We show that in high transmission rate settings, falling population immunity after OPV cessation will lead to conditions in which OPV and WPV are similarly capable of causing outbreaks, and that this conclusion is compatible with the known safety of OPV prior to global cessation. Novel strategies will be required to ensure the stability of polio eradication for all time.
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Affiliation(s)
- Michael Famulare
- Institute for Disease Modeling, Bellevue, Washington, United States of America
- * E-mail:
| | - Christian Selinger
- Institute for Disease Modeling, Bellevue, Washington, United States of America
| | - Kevin A. McCarthy
- Institute for Disease Modeling, Bellevue, Washington, United States of America
| | - Philip A. Eckhoff
- Institute for Disease Modeling, Bellevue, Washington, United States of America
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Duintjer Tebbens RJ, Hampton LM, Thompson KM. Planning for globally coordinated cessation of bivalent oral poliovirus vaccine: risks of non-synchronous cessation and unauthorized oral poliovirus vaccine use. BMC Infect Dis 2018; 18:165. [PMID: 29631539 PMCID: PMC5892013 DOI: 10.1186/s12879-018-3074-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 03/28/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Oral polio vaccine (OPV) containing attenuated serotype 2 polioviruses was globally withdrawn in 2016, and bivalent OPV (bOPV) containing attenuated serotype 1 and 3 polioviruses needs to be withdrawn after the certification of eradication of all wild polioviruses to eliminate future risks from vaccine-derived polioviruses (VDPVs). To minimize risks from VDPVs, the planning and implementation of bOPV withdrawal should build on the experience with withdrawing OPV containing serotype 2 polioviruses while taking into account similarities and differences between the three poliovirus serotypes. METHODS We explored the risks from (i) a failure to synchronize OPV cessation and (ii) unauthorized post-cessation OPV use for serotypes 1 and 3 in the context of globally-coordinated future bOPV cessation and compared the results to similar analyses for serotype 2 OPV cessation. RESULTS While the risks associated with a failure to synchronize cessation and unauthorized post-cessation OPV use appear to be substantially lower for serotype 3 polioviruses than for serotype 2 polioviruses, the risks for serotype 1 appear similar to those for serotype 2. Increasing population immunity to serotype 1 and 3 poliovirus transmission using pre-cessation bOPV supplemental immunization activities and inactivated poliovirus vaccine in routine immunization reduces the risks of circulating VDPVs associated with non-synchronized cessation or unauthorized OPV use. CONCLUSIONS The Global Polio Eradication Initiative should synchronize global bOPV cessation during a similar window of time as occurred for the global cessation of OPV containing serotype 2 polioviruses and should rigorously verify the absence of bOPV in immunization systems after its cessation.
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Affiliation(s)
| | - Lee M. Hampton
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA USA
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Duizer E, Ruijs WL, van der Weijden CP, Timen A. Response to a wild poliovirus type 2 (WPV2)-shedding event following accidental exposure to WPV2, the Netherlands, April 2017. ACTA ACUST UNITED AC 2018; 22:30542. [PMID: 28597830 PMCID: PMC5479986 DOI: 10.2807/1560-7917.es.2017.22.21.30542] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 05/18/2017] [Indexed: 11/20/2022]
Abstract
On 3 April 2017, a wild poliovirus type 2 (WPV2) spill occurred in a Dutch vaccine manufacturing plant. Two fully vaccinated operators with risk of exposure were advised on stringent personal hygiene and were monitored for virus shedding. Poliovirus (WPV2-MEF1) was detected in the stool of one, 4 days after exposure, later also in sewage samples. The operator was isolated at home and followed up until shedding stopped 29 days after exposure. No further transmission was detected.
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Affiliation(s)
- Erwin Duizer
- Centre for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Wilhelmina Lm Ruijs
- Centre for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | | | - Aura Timen
- Centre for Infectious Diseases Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
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Duintjer Tebbens RJ, Zimmermann M, Pallansch M, Thompson KM. Insights from a Systematic Search for Information on Designs, Costs, and Effectiveness of Poliovirus Environmental Surveillance Systems. FOOD AND ENVIRONMENTAL VIROLOGY 2017; 9:361-382. [PMID: 28687986 PMCID: PMC7879701 DOI: 10.1007/s12560-017-9314-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/30/2017] [Indexed: 05/20/2023]
Abstract
Poliovirus surveillance plays a critical role in achieving and certifying eradication and will play a key role in the polio endgame. Environmental surveillance can provide an opportunity to detect circulating polioviruses prior to the observation of any acute flaccid paralysis cases. We completed a systematic review of peer-reviewed publications on environmental surveillance for polio including the search terms "environmental surveillance" or "sewage," and "polio," "poliovirus," or "poliomyelitis," and compared characteristics of the resulting studies. The review included 146 studies representing 101 environmental surveillance activities from 48 countries published between 1975 and 2016. Studies reported taking samples from sewage treatment facilities, surface waters, and various other environmental sources, although they generally did not present sufficient details to thoroughly evaluate the sewage systems and catchment areas. When reported, catchment areas varied from 50 to over 7.3 million people (median of 500,000 for the 25% of activities that reported catchment areas, notably with 60% of the studies not reporting this information and 16% reporting insufficient information to estimate the catchment area population size). While numerous studies reported the ability of environmental surveillance to detect polioviruses in the absence of clinical cases, the review revealed very limited information about the costs and limited information to support quantitative population effectiveness of conducting environmental surveillance. This review motivates future studies to better characterize poliovirus environmental surveillance systems and the potential value of information that they may provide in the polio endgame.
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Affiliation(s)
| | - Marita Zimmermann
- Kid Risk, Inc., 10524 Moss Park Rd., Ste. 204-364, Orlando, FL 32832
- Correspondence to: Radboud J. Duintjer Tebbens, Kid Risk, Inc., 10524 Moss Park Rd., Ste. 204-364, Orlando, FL 32832, USA,
| | - Mark Pallansch
- Centers for Disease Control and Prevention, Division of Viral Diseases, Atlanta, GA 30333
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Bandyopadhyay AS, Asturias EJ, O'Ryan M, Oberste MS, Weldon W, Clemens R, Rüttimann R, Modlin JF, Gast C. Exploring the relationship between polio type 2 serum neutralizing antibodies and intestinal immunity using data from two randomized controlled trials of new bOPV-IPV immunization schedules. Vaccine 2017; 35:7283-7291. [PMID: 29150209 PMCID: PMC5725506 DOI: 10.1016/j.vaccine.2017.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/18/2017] [Accepted: 11/03/2017] [Indexed: 11/24/2022]
Abstract
BACKGROUND Inactivated polio vaccine (IPV) is now the only source of routine type 2 protection. The relationship, if any, between vaccine-induced type 2 humoral and intestinal immunity is poorly understood. METHODS Two clinical trials in five Latin American countries of mixed or sequential bOPV-IPV schedules in 1640 infants provided data on serum neutralizing antibodies (NAb) and intestinal immunity, assessed as viral shedding following oral mOPV2 challenge. Analyses with generalized additive and quantile regression models examined the relationships between prechallenge NAb titers and proportion, duration and titers (magnitude) of viral shedding. RESULTS We found a statistically significant (p < .0001) but weak relationship between NAb titer at the time of mOPV2 challenge and the Shedding Index Endpoint, the mean log10 stool viral titer over 4 post-challenge assessments. Day 28 post-challenge shedding was 13.4% (8.1%, 18.8%) lower and the Day 21 post-challenge median titer of shed virus was 3.10 log10 (2.21, 3.98) lower for subjects with NAb titers at the ULOQ as compared with LLOQ on day of challenge. Overall, there was a weak but significant negative relationship, with high NAb titers associated with lower rates of viral shedding, an effect supported by subset analysis to elucidate between-country differences. CONCLUSIONS Taken alone, the weak association between pre-challenge NAb titers following IPV or mixed/sequential bOPV/IPV immunization and differences in intestinal immunity is insufficient to predict polio type 2 intestinal immunity; even very high titers may not preclude viral shedding. Further research is needed to identify predictive markers of intestinal immunity in the context of global OPV cessation and IPV-only immunization.
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Affiliation(s)
| | - Edwin J Asturias
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA; Center for Global Health and Department of Epidemiology, Colorado School of Public Health, Aurora, CO, USA
| | - Miguel O'Ryan
- Millennium Institute of Immunology and Immunotherapy, Faculty of Medicine, University of Chile, Santiago, Chile
| | | | - William Weldon
- Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ralf Clemens
- Global Research in Infectious Diseases (GRID), Rio de Janeiro, Brazil
| | - Ricardo Rüttimann
- Fighting Infectious Diseases in Emerging Countries (FIDEC), Miami, FL, USA
| | | | - Chris Gast
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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Bull JJ, Smithson MW, Nuismer SL. Transmissible Viral Vaccines. Trends Microbiol 2017; 26:6-15. [PMID: 29033339 PMCID: PMC5777272 DOI: 10.1016/j.tim.2017.09.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/15/2017] [Accepted: 09/22/2017] [Indexed: 12/28/2022]
Abstract
Genetic engineering now enables the design of live viral vaccines that are potentially transmissible. Some designs merely modify a single viral genome to improve on the age-old method of attenuation whereas other designs create chimeras of viral genomes. Transmission has the benefit of increasing herd immunity above that achieved by direct vaccination alone but also increases the opportunity for vaccine evolution, which typically undermines vaccine utility. Different designs have different epidemiological consequences but also experience different evolution. Approaches that integrate vaccine engineering with an understanding of evolution and epidemiology will reap the greatest benefit from vaccine transmission.
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Affiliation(s)
- James J Bull
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78712 USA.
| | - Mark W Smithson
- School of Biological Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Scott L Nuismer
- Department of Biological Sciences, Department of Mathematics, University of Idaho, Moscow, ID, 83844, USA.
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Ferreyra-Reyes L, Cruz-Hervert LP, Troy SB, Huang C, Sarnquist C, Delgado-Sánchez G, Canizales-Quintero S, Holubar M, Ferreira-Guerrero E, Montero-Campos R, Rodríguez-Álvarez M, Mongua-Rodriguez N, Maldonado Y, García-García L. Assessing the individual risk of fecal poliovirus shedding among vaccinated and non-vaccinated subjects following national health weeks in Mexico. PLoS One 2017; 12:e0185594. [PMID: 29023555 PMCID: PMC5638237 DOI: 10.1371/journal.pone.0185594] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 09/15/2017] [Indexed: 11/21/2022] Open
Abstract
Background Mexico introduced inactivated polio vaccine (IPV) into its routine immunization (RI) schedule in 2007 but continued to give trivalent oral polio vaccine (tOPV) twice a year during national health weeks (NHW) through 2015. Objectives To evaluate individual variables associated with poliovirus (PV) shedding among children with IPV-induced immunity after vaccination with tOPV and their household contacts. Materials and methods We recruited 72 children (both genders, ≤30 months, vaccinated with at least two doses of IPV) and 144 household contacts (both genders, 2 per household, children and adults) between 08/2010 and 09/2010 in Orizaba, Veracruz. Three NHW took place (one before and two after enrollment). We collected fecal samples monthly for 12 months, and tested 2500 samples for polioviruses types 1, 2 and 3 with three serotype-specific singleplex real-time RT-PCR (rRT-PCR) assays. In order to increase the specificity for OPV virus, all positive and 112 negative samples were also processed with a two-step, OPV serotype-specific multiplex rRT-PCR. Analysis We estimated adjusted hazard ratios (HR) and 95% CI using Cox proportional hazards regression for recurrent events models accounting for individual clustering to assess the association of individual variables with the shedding of any poliovirus for all participants and stratifying according to whether the participant had received tOPV in the month of sample collection. Results 216 participants were included. Of the 2500 collected samples, using the singleplex rRT-PCR assay, PV was detected in 5.7% (n = 142); PV1 in 1.2% (n = 29), PV2 in 4.1% (n = 103), and PV3 in 1.9% (n = 48). Of the 256 samples processed by multiplex rRT-PCR, PV was detected in 106 (PV1 in 16.41% (n = 42), PV2 in 21.09% (n = 54), and PV3 in 23.05% (n = 59). Both using singleplex and multiplex assays, shedding of OPV among non-vaccinated children and subjects older than 5 years of age living in the same household was associated with shedding of PV2 by a household contact. All models were adjusted by sex, age, IPV vaccination and OPV shedding by the same individual during the previous month of sample collection. Conclusion Our results provide important evidence regarding the circulation of poliovirus in a mixed vaccination context (IPV+OPV) which mimics the “transitional phase” that occurs when countries use both vaccines simultaneously. Shedding of OPV2 by household contacts was most likely the source of infection of non-vaccinated children and subjects older than 5 years of age living in the same household.
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Affiliation(s)
| | | | - Stephanie B. Troy
- Eastern Virginia Medical School, Norfolk, Virginia, United States of America
| | - ChunHong Huang
- Stanford University School of Medicine, Stanford, California, United States of America
| | - Clea Sarnquist
- Stanford University School of Medicine, Stanford, California, United States of America
| | | | | | - Marisa Holubar
- Stanford University School of Medicine, Stanford, California, United States of America
| | | | | | | | | | - Yvonne Maldonado
- Stanford University School of Medicine, Stanford, California, United States of America
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Abstract
BACKGROUND Wild type 2 poliovirus was last observed in 1999. The Sabin-strain oral polio vaccine type 2 (OPV2) was critical to eradication, but it is known to revert to a neurovirulent phenotype, causing vaccine-associated paralytic poliomyelitis. OPV2 is also transmissible and can establish circulating lineages, called circulating vaccine-derived polioviruses (cVDPVs), which can also cause paralytic outbreaks. Thus, in April 2016, OPV2 was removed from immunization activities worldwide. Interrupting transmission of cVDPV2 lineages that survive cessation will require OPV2 in outbreak response, which risks seeding new cVDPVs. This potential cascade of outbreak responses seeding VDPVs, necessitating further outbreak responses, presents a critical risk to the OPV2 cessation effort. METHODS The EMOD individual-based disease transmission model was used to investigate OPV2 use in outbreak response post-cessation in West African populations. A hypothetical outbreak response in northwest Nigeria is modeled, and a cVDPV2 lineage is considered established if the Sabin strain escapes the response region and continues circulating 9 months post-response. The probability of this event was investigated in a variety of possible scenarios. RESULTS Under a broad range of scenarios, the probability that widespread OPV2 use in outbreak response (~2 million doses) establishes new cVDPV2 lineages in this model may exceed 50% as soon as 18 months or as late as 4 years post-cessation. CONCLUSIONS The risk of a cycle in which outbreak responses seed new cVDPV2 lineages suggests that OPV2 use should be managed carefully as time from cessation increases. It is unclear whether this risk can be mitigated in the long term, as mucosal immunity against type 2 poliovirus declines globally. Therefore, current programmatic strategies should aim to minimize the possibility that continued OPV2 use will be necessary in future years: conducting rapid and aggressive outbreak responses where cVDPV2 lineages are discovered, maintaining high-quality surveillance in all high-risk settings, strengthening the use of the inactivated polio vaccine as a booster in the OPV2-exposed and in routine immunization, and gaining access to currently inaccessible areas of the world to conduct surveillance.
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Dénes A, Székely L. Global dynamics of a mathematical model for the possible re-emergence of polio. Math Biosci 2017; 293:64-74. [PMID: 28859911 DOI: 10.1016/j.mbs.2017.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 08/03/2017] [Accepted: 08/25/2017] [Indexed: 11/26/2022]
Abstract
Motivated by studies warning about a possible re-emergence of poliomyelitis in Europe, we analyse a compartmental model for the transmission of polio describing the possible effect of unvaccinated people arriving to a region with low vaccination coverage. We calculate the basic reproduction number, and determine the global dynamics of the system: we show that, depending on the parameters, one of the two equilibria is globally asymptotically stable. The main tools applied are Lyapunov functions and persistence theory. We illustrate the analytic results by numerical examples, which also suggest that in order to avoid the risk of polio re-emergence, vaccinating the immigrant population might result insufficient, and also the vaccination coverage of countries with low rates should be increased.
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Affiliation(s)
- Attila Dénes
- Bolyai Institute, University of Szeged, Aradi vértanúk tere 1., Szeged H-6720, Hungary.
| | - László Székely
- Institute for Environmental Systems, Szent István University, Páter Károly utca 1., Gödöllő H-2103, Hungary
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Taniuchi M, Famulare M, Zaman K, Uddin MJ, Upfill-Brown AM, Ahmed T, Saha P, Haque R, Bandyopadhyay AS, Modlin JF, Platts-Mills JA, Houpt ER, Yunus M, Petri WA. Community transmission of type 2 poliovirus after cessation of trivalent oral polio vaccine in Bangladesh: an open-label cluster-randomised trial and modelling study. THE LANCET. INFECTIOUS DISEASES 2017; 17:1069-1079. [PMID: 28693854 PMCID: PMC5610141 DOI: 10.1016/s1473-3099(17)30358-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/28/2017] [Accepted: 05/30/2017] [Indexed: 01/12/2023]
Abstract
Background Trivalent oral polio vaccine (tOPV) was replaced worldwide from April, 2016, by bivalent types 1 and 3 oral polio vaccine (bOPV) and one dose of inactivated polio vaccine (IPV) where available. The risk of transmission of type 2 poliovirus or Sabin 2 virus on re-introduction or resurgence of type 2 poliovirus after this switch is not understood completely. We aimed to assess the risk of Sabin 2 transmission after a polio vaccination campaign with a monovalent type 2 oral polio vaccine (mOPV2). Methods We did an open-label cluster-randomised trial in villages in the Matlab region of Bangladesh. We randomly allocated villages (clusters) to either: tOPV at age 6 weeks, 10 weeks, and 14 weeks; or bOPV at age 6 weeks, 10 weeks, and 14 weeks and either one dose of IPV at age 14 weeks or two doses of IPV at age 14 weeks and 18 weeks. After completion of enrolment, we implemented an mOPV2 vaccination campaign that targeted 40% of children younger than 5 years, regardless of enrolment status. The primary outcome was Sabin 2 incidence in the 10 weeks after the campaign in per-protocol infants who did not receive mOPV2, as assessed by faecal shedding of Sabin 2 by reverse transcriptase quantitative PCR (RT-qPCR). The effect of previous immunity on incidence was also investigated with a dynamical model of poliovirus transmission to observe prevalence and incidence of Sabin 2 virus. This trial is registered at ClinicalTrials.gov, number NCT02477046. Findings Between April 30, 2015, and Jan 14, 2016, individuals from 67 villages were enrolled to the study. 22 villages (300 infants) were randomly assigned tOPV, 23 villages (310 infants) were allocated bOPV and one dose of IPV, and 22 villages (329 infants) were assigned bOPV and two doses of IPV. Faecal shedding of Sabin 2 in infants who did not receive the mOPV2 challenge did not differ between children immunised with bOPV and one or two doses of IPV and those who received tOPV (15 of 252 [6%] vs six of 122 [4%]; odds ratio [OR] 1·29, 95% CI 0·45–3·72; p=0·310). However, faecal shedding of Sabin 2 in household contacts was increased significantly with bOPV and one or two doses of IPV compared with tOPV (17 of 751 [2%] vs three of 353 [1%]; OR 3·60, 95% CI 0·82–15·9; p=0·045). Dynamical modelling of within-household incidence showed that immunity in household contacts limited transmission. Interpretation In this study, simulating 1 year of tOPV cessation, Sabin 2 transmission was higher in household contacts of mOPV2 recipients in villages receiving bOPV and either one or two doses of IPV, but transmission was not increased in the community as a whole as shown by the non-significant difference in incidence among infants. Dynamical modelling indicates that transmission risk will be higher with more time since cessation. Funding Bill & Melinda Gates Foundation.
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Affiliation(s)
- Mami Taniuchi
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA.
| | - Michael Famulare
- Institute for Disease Modeling, Global Good, Intellectual Ventures, Bellevue, WA, USA
| | - Khalequ Zaman
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Md Jashim Uddin
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
| | | | - Tahmina Ahmed
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Parimalendu Saha
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Rashidul Haque
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | | | | | - James A Platts-Mills
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
| | - Eric R Houpt
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
| | - Mohammed Yunus
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - William A Petri
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA
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Duintjer Tebbens RJ, Thompson KM. Modeling the costs and benefits of temporary recommendations for poliovirus exporting countries to vaccinate international travelers. Vaccine 2017; 35:3823-3833. [PMID: 28606811 PMCID: PMC5488262 DOI: 10.1016/j.vaccine.2017.05.090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 05/31/2017] [Accepted: 05/31/2017] [Indexed: 11/27/2022]
Abstract
Recognizing that infectious agents readily cross international borders, the International Health Regulations Emergency Committee issues Temporary Recommendations (TRs) that include vaccination of travelers from countries affected by public health emergencies, including serotype 1 wild polioviruses (WPV1s). This analysis estimates the costs and benefits of TRs implemented by countries with reported WPV1 during 2014-2016 while accounting for numerous uncertainties. We estimate the TR costs based on programmatic data and prior economic analyses and TR benefits by simulating potential WPV1 outbreaks in the absence of the TRs using the rate and extent of WPV1 importation outbreaks per reported WPV1 case during 2004-2013 and the number of reported WPV1 cases that occurred in countries with active TRs. The benefits of TRs outweigh the costs in 77% of model iterations, resulting in expected incremental net economic benefits of $210 million. Inclusion of indirect costs increases the costs by 13%, the expected savings from prevented outbreaks by 4%, and the expected incremental net benefits by 3%. Despite the considerable costs of implementing TRs, this study provides health and economic justification for these investments in the context of managing a disease in advanced stages of its global eradication.
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Fontana S, Buttinelli G, Fiore S, Mulaomerovic M, Aćimović J, Amato C, Delogu R, Rezza G, Stefanelli P. Acute flaccid paralysis surveillance in bosnia and herzegovina: Recent isolation of two sabin like type 2 poliovirus. J Med Virol 2017; 89:1678-1681. [PMID: 28390186 DOI: 10.1002/jmv.24827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/19/2017] [Indexed: 11/06/2022]
Abstract
The WHO Regional Commission for the Certification of Poliomyelitis Eradication has recently indicated Bosnia and Herzegovina (B&H) as a high risk country for transmission, following importation, of wild poliovirus (WPV) or circulating vaccine-derived poliovirus (cVDPV). We analyzed data on Acute Flaccid Paralysis (AFP) surveillance between 2007 to 2016, and the trend of polio immunization coverage in B&H. The majority of AFP cases was recorded in 2016 suggesting an enhancement of the AFP surveillance activities. However, the decline in the immunization coverage, around 74%, and the isolation of two Sabin-like poliovirus type 2 strains, one of them close to a VDPV, require a particular attention in the area. Although B&H has successfully maintained its polio-free status since 2002 several challenges need to be addressed.
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Affiliation(s)
- Stefano Fontana
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Gabriele Buttinelli
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Stefano Fiore
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Mirsada Mulaomerovic
- Department of Epidemiology, Institute for Public Health of Federation Bosnia and Herzegovina, Sarajevo, Bosnia and Herzegovina
| | - Jela Aćimović
- Department of Epidemiology, Public Health Institute of the Republic of Srpska
| | - Concetta Amato
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Roberto Delogu
- National Center for the Control and Evaluation of Medicines, Istituto Superiore di Sanità, Rome, Italy
| | - Giovanni Rezza
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Paola Stefanelli
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy.,WHO Polio Regional Reference Laboratory, c/o Istituto Superiore di Sanità, Rome, Italy
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Giri S, Rajan AK, Kumar N, Dhanapal P, Venkatesan J, Iturriza-Gomara M, Taniuchi M, John J, Abraham AM, Kang G. Comparison of culture, single and multiplex real-time PCR for detection of Sabin poliovirus shedding in recently vaccinated Indian children. J Med Virol 2017; 89:1485-1488. [PMID: 28213965 PMCID: PMC6139431 DOI: 10.1002/jmv.24793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 01/30/2017] [Indexed: 11/30/2022]
Abstract
Although, culture is considered the gold standard for poliovirus detection from stool samples, real‐time PCR has emerged as a faster and more sensitive alternative. Detection of poliovirus from the stool of recently vaccinated children by culture, single and multiplex real‐time PCR was compared. Of the 80 samples tested, 55 (68.75%) were positive by culture compared to 61 (76.25%) and 60 (75%) samples by the single and one step multiplex real‐time PCR assays respectively. Real‐time PCR (singleplex and multiplex) is more sensitive than culture for poliovirus detection in stool, although the difference was not statistically significant.
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Affiliation(s)
- Sidhartha Giri
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Anand K Rajan
- Department of Clinical Virology, Christian Medical College, Vellore, India
| | - Nirmal Kumar
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Pavithra Dhanapal
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | | | - Miren Iturriza-Gomara
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Mami Taniuchi
- Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Jacob John
- Department of Community Medicine, Christian Medical College, Vellore, India
| | - Asha Mary Abraham
- Department of Clinical Virology, Christian Medical College, Vellore, India
| | - Gagandeep Kang
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
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Koopman JS, Henry CJ, Park JH, Eisenberg MC, Ionides EL, Eisenberg JN. Dynamics affecting the risk of silent circulation when oral polio vaccination is stopped. Epidemics 2017; 20:21-36. [PMID: 28283373 PMCID: PMC5608688 DOI: 10.1016/j.epidem.2017.02.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 02/20/2017] [Accepted: 02/20/2017] [Indexed: 12/15/2022] Open
Abstract
Silent circulation (SC) of wild polio viruses (WPV) when oral polio vaccine (OPV) use is stopped, could threaten eradication. We analyzed a model designed to develop theory about mechanisms and factors that lead to SC and how SC risks can be assessed using surveillance data. Prolonged low-level SC emerges as a threshold phenomenon through a mechanism related to balancing contributions of different populations to the effective reproduction number. Factors that promote this mechanism are many years of inadequate vaccination efforts, ongoing waning of immunity against transmission years after last OPV or WPV infection, low transmissibility of OPV, and high transmission conditions. Analyzing acute flaccid paralysis surveillance or environmental surveillance data by themselves cannot assess the risk that an SC threshold has been passed, but new methods to analyze them jointly could do so.
Waning immunity could allow transmission of polioviruses without causing poliomyelitis by promoting silent circulation (SC). Undetected SC when oral polio vaccine (OPV) use is stopped could cause difficult to control epidemics. Little is known about waning. To develop theory about what generates SC, we modeled a range of waning patterns. We varied both OPV and wild polio virus (WPV) transmissibility, the time from beginning vaccination to reaching low polio levels, and the infection to paralysis ratio (IPR). There was longer SC when waning continued over time rather than stopping after a few years, when WPV transmissibility was higher or OPV transmissibility was lower, and when the IPR was higher. These interacted in a way that makes recent emergence of prolonged SC a possibility. As the time to reach low infection levels increased, vaccine rates needed to eliminate polio increased and a threshold was passed where prolonged low-level SC emerged. These phenomena were caused by increased contributions to the force of infection from reinfections. The resulting SC occurs at low levels that would be difficult to detect using environmental surveillance. For all waning patterns, modest levels of vaccination of adults shortened SC. Previous modeling studies may have missed these phenomena because (1) they used models with no or very short duration waning and (2) they fit models to paralytic polio case counts. Our analyses show that polio case counts cannot predict SC because nearly identical polio case count patterns can be generated by a range of waning patterns that generate different patterns of SC. We conclude that the possibility of prolonged SC is real but unquantified, that vaccinating modest fractions of adults could reduce SC risk, and that joint analysis of acute flaccid paralysis and environmental surveillance data can help assess SC risks and ensure low risks before stopping OPV.
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Affiliation(s)
- J S Koopman
- Department of Epidemiology, University of Michigan School of Public Health, United States.
| | - C J Henry
- Department of Epidemiology, University of Michigan School of Public Health, United States
| | - J H Park
- Department of Statistics, University of Michigan School of Literature, Science, and the Arts, United States
| | - M C Eisenberg
- Department of Epidemiology, University of Michigan School of Public Health, United States
| | - E L Ionides
- Department of Statistics, University of Michigan School of Literature, Science, and the Arts, United States
| | - J N Eisenberg
- Department of Epidemiology, University of Michigan School of Public Health, United States
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Abstract
Infections of the nervous system are an important and challenging aspect of clinical neurology. Immediate correct diagnosis enables to introduce effective therapy, in conditions that without diagnosis may leave the patient with severe neurological incapacitation and sometimes even death. The cerebrospinal fluid (CSF) is a mirror that reflects nervous system pathology and can promote early diagnosis and therapy. The present chapter focuses on the CSF findings in neuro-infections, mainly viral and bacterial. Opening pressure, protein and glucose levels, presence of cells and type of the cellular reaction should be monitored. Other tests can also shed light on the causative agent: serology, culture, staining, molecular techniques such as polymerase chain reaction. Specific examination such as panbacterial and panfungal examinations should be examined when relevant. Our chapter is a guide-text that combines clinical presentation and course with CSF findings as a usuaful tool in diagnosis of neuroinfections.
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Affiliation(s)
- Felix Benninger
- Department of Neurology, Rabin Medical Center, Petach Tikva, Israel
| | - Israel Steiner
- Department of Neurology, Rabin Medical Center, Petach Tikva, Israel
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Duintjer Tebbens RJ, Thompson KM. Costs and Benefits of Including Inactivated in Addition to Oral Poliovirus Vaccine in Outbreak Response After Cessation of Oral Poliovirus Vaccine Use. MDM Policy Pract 2017; 2:2381468317697002. [PMID: 30288417 PMCID: PMC6124926 DOI: 10.1177/2381468317697002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 12/02/2016] [Indexed: 01/24/2023] Open
Abstract
Background: After stopping serotype 2-containing oral poliovirus vaccine use, serotype 2 poliovirus outbreaks may still occur and require outbreak response supplemental immunization activities (oSIAs). Current oSIA plans include the use of both serotype 2 monovalent oral poliovirus vaccine (mOPV2) and inactivated poliovirus vaccine (IPV). Methods: We used an existing model to compare the effectiveness of mOPV2 oSIAs with or without IPV in response to a hypothetical postcessation serotype 2 outbreak in northwest Nigeria. We considered strategies that co-administer IPV with mOPV2, use IPV only for older age groups, or use only IPV during at least one oSIA. We considered the cost and supply implications and estimated from a societal perspective the incremental cost-effectiveness and incremental net benefits of adding IPV to oSIAs in the context of this hypothetical outbreak in 2017. Results: Adding IPV to the first or second oSIA resulted in a 4% to 6% reduction in expected polio cases compared to exclusive mOPV2 oSIAs. We found the greatest benefit of IPV use if added preemptively as a ring around the initial oSIA target population, and negligible benefit if added to later oSIAs or older age groups. We saw an increase in expected polio cases if IPV replaced mOPV2 during an oSIA. None of the oSIA strategies that included IPV for this outbreak represented a cost-effective or net beneficial intervention compared to reliance on mOPV2 only. Conclusions: While adding IPV to oSIAs results in marginal improvements in performance, the poor cost-effectiveness and current limited IPV supply make it economically unattractive for high-risk settings in which IPV does not significantly affect transmission.
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Duintjer Tebbens RJ, Thompson KM. The potential benefits of a new poliovirus vaccine for long-term poliovirus risk management. Future Microbiol 2016; 11:1549-1561. [DOI: 10.2217/fmb-2016-0126] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Aim: To estimate the incremental net benefits (INBs) of a hypothetical ideal vaccine with all of the advantages and no disadvantages of existing oral and inactivated poliovirus vaccines compared with current vaccines available for future outbreak response. Methods: INB estimates based on expected costs and polio cases from an existing global model of long-term poliovirus risk management. Results: Excluding the development costs, an ideal poliovirus vaccine could offer expected INBs of US$1.6 billion. The ideal vaccine yields small benefits in most realizations of long-term risks, but great benefits in low-probability–high-consequence realizations. Conclusion: New poliovirus vaccines may offer valuable insurance against long-term poliovirus risks and new vaccine development efforts should continue as the world gathers more evidence about polio endgame risks.
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Comprehensive screening for immunodeficiency-associated vaccine-derived poliovirus: an essential oral poliovirus vaccine cessation risk management strategy. Epidemiol Infect 2016; 145:217-226. [PMID: 27760579 PMCID: PMC5197684 DOI: 10.1017/s0950268816002302] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
If the world can successfully control all outbreaks of circulating vaccine-derived poliovirus that may occur soon after global oral poliovirus vaccine (OPV) cessation, then immunodeficiency-associated vaccine-derived polioviruses (iVDPVs) from rare and mostly asymptomatic long-term excretors (defined as ⩾6 months of excretion) will become the main source of potential poliovirus outbreaks for as long as iVDPV excretion continues. Using existing models of global iVDPV prevalence and global long-term poliovirus risk management, we explore the implications of uncertainties related to iVDPV risks, including the ability to identify asymptomatic iVDPV excretors to treat with polio antiviral drugs (PAVDs) and the transmissibility of iVDPVs. The expected benefits of expanded screening to identify and treat long-term iVDPV excretors with PAVDs range from US$0.7 to 1.5 billion with the identification of 25–90% of asymptomatic long-term iVDPV excretors, respectively. However, these estimates depend strongly on assumptions about the transmissibility of iVDPVs and model inputs affecting the global iVDPV prevalence. For example, the expected benefits may decrease to as low as US$260 million with the identification of 90% of asymptomatic iVDPV excretors if iVDPVs behave and transmit like partially reverted viruses instead of fully reverted viruses. Comprehensive screening for iVDPVs will reduce uncertainties and maximize the expected benefits of PAVD use.
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Tebbens RJD, Hampton LM, Wassilak SGF, Pallansch MA, Cochi SL, Thompson KM. Maintenance and Intensification of Bivalent Oral Poliovirus Vaccine Use Prior to its Coordinated Global Cessation. JOURNAL OF VACCINES & VACCINATION 2016; 7:340. [PMID: 28690915 PMCID: PMC5497833 DOI: 10.4172/2157-7560.1000340] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To examine the impact of different bivalent oral poliovirus vaccine (bOPV) supplemental immunization activity (SIA) strategies on population immunity to serotype 1 and 3 poliovirus transmission and circulating vaccine-derived poliovirus (cVDPV) risks before and after globally-coordinated cessation of serotype 1 and 3 oral poliovirus vaccine (OPV13 cessation). METHODS We adapt mathematical models that previously informed vaccine choices ahead of the trivalent oral poliovirus vaccine to bOPV switch to estimate the population immunity to serotype 1 and 3 poliovirus transmission needed at the time of OPV13 cessation to prevent subsequent cVDPV outbreaks. We then examine the impact of different frequencies of SIAs using bOPV in high risk populations on population immunity to serotype 1 and 3 transmission, on the risk of serotype 1 and 3 cVDPV outbreaks, and on the vulnerability to any imported bOPV-related polioviruses. RESULTS Maintaining high population immunity to serotype 1 and 3 transmission using bOPV SIAs significantly reduces 1) the risk of outbreaks due to imported serotype 1 and 3 viruses, 2) the emergence of indigenous cVDPVs before or after OPV13 cessation, and 3) the vulnerability to bOPV-related polioviruses in the event of non-synchronous OPV13 cessation or inadvertent bOPV use after OPV13 cessation. CONCLUSION Although some reduction in global SIA frequency can safely occur, countries with suboptimal routine immunization coverage should each continue to conduct at least one annual SIA with bOPV, preferably more, until global OPV13 cessation. Preventing cVDPV risks after OPV13 cessation requires investments in bOPV SIAs now through the time of OPV13 cessation.
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Affiliation(s)
| | - Lee M Hampton
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Steven G F Wassilak
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Mark A Pallansch
- Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Stephen L Cochi
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Wright PF, Connor RI, Wieland-Alter WF, Hoen AG, Boesch AW, Ackerman ME, Oberste MS, Gast C, Brickley EB, Asturias EJ, Rüttimann R, Bandyopadhyay AS. Vaccine-induced mucosal immunity to poliovirus: analysis of cohorts from an open-label, randomised controlled trial in Latin American infants. THE LANCET. INFECTIOUS DISEASES 2016; 16:1377-1384. [PMID: 27638357 PMCID: PMC5611465 DOI: 10.1016/s1473-3099(16)30169-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 05/03/2016] [Accepted: 06/06/2016] [Indexed: 01/23/2023]
Abstract
Background Identification of mechanisms that limit poliovirus replication is crucial for informing decisions aimed at global polio eradication. Studies of mucosal immunity induced by oral poliovirus (OPV) or inactivated poliovirus (IPV) vaccines and mixed schedules thereof will determine the effectiveness of different vaccine strategies to block virus shedding. We used samples from a clinical trial of different vaccination schedules to measure intestinal immunity as judged by neutralisation of virus and virus-specific IgA in stools. Methods In the FIDEC trial, Latin American infants were randomly assigned to nine groups to assess the efficacy of two schedules of bivalent OPV (bOPV) and IPV and challenge with monovalent type 2 OPV, and stools samples were collected. We selected three groups of particular interest—the bOPV control group (serotypes 1 and 3 at 6, 10, and 14 weeks), the trivalent attenuated OPV (tOPV) control group (tOPV at 6, 10, and 14 weeks), and the bOPV–IPV group (bOPV at 6, 10, and 14 weeks plus IPV at 14 weeks). Neutralising activity and poliovirus type-specific IgA were measured in stool after a monovalent OPV type 2 challenge at 18 weeks of age. Mucosal immunity was measured by in-vitro neutralisation of a type 2 polio pseudovirus (PV2). Neutralisation titres and total and poliovirus-type-specific IgG and IgA concentrations in stools were assessed in samples collected before challenge and 2 weeks after challenge from all participants. Findings 210 infants from Guatemala and Dominican Republic were included in this analysis. Of 38 infants tested for mucosal antibody in the tOPV group, two were shedding virus 1 week after challenge, compared with 59 of 85 infants receiving bOPV (p<0·0001) and 53 of 87 infants receiving bOPV–IPV (p<0·0001). Mucosal type 2 neutralisation and type-specific IgA were noted primarily in response to tOPV. An inverse correlation was noted between virus shedding and both serum type 2 neutralisation at challenge (p<0·0001) and mucosal type 2 neutralisation at challenge (p<0·0001). Interpretation Mucosal type-2-specific antibodies can be measured in stool and develop in response to receipt of OPV type 2 either in the primary vaccine series or at challenge. These mucosal antibodies influence the amount of virus that is shed in an established infection. Funding Bill & Melinda Gates Foundation.
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Affiliation(s)
- Peter F Wright
- Department of Pediatrics, Dartmouth College, Hanover, NH, USA.
| | - Ruth I Connor
- Department of Microbiology and Immunology, Dartmouth College, Hanover, NH, USA
| | | | - Anne G Hoen
- Department of Epidemiology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Austin W Boesch
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | | | | | - Chris Gast
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Elizabeth B Brickley
- Department of Epidemiology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Edwin J Asturias
- Departments of Pediatrics and Epidemiology, University of Colorado Denver School of Medicine, Aurora, CO, USA
| | - Ricardo Rüttimann
- Fighting Infectious Diseases in Emerging Countries (FIDEC), Miami, FL, USA
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Duintjer Tebbens RJ, Hampton LM, Thompson KM. Implementation of coordinated global serotype 2 oral poliovirus vaccine cessation: risks of inadvertent trivalent oral poliovirus vaccine use. BMC Infect Dis 2016; 16:237. [PMID: 27246198 PMCID: PMC4888482 DOI: 10.1186/s12879-016-1537-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/04/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The endgame for polio eradication includes coordinated global cessation of oral poliovirus vaccine (OPV), starting with the cessation of vaccine containing OPV serotype 2 (OPV2) by switching all trivalent OPV (tOPV) to bivalent OPV (bOPV). The logistics associated with this global switch represent a significant undertaking, with some possibility of inadvertent tOPV use after the switch. METHODS We used a previously developed poliovirus transmission and OPV evolution model to explore the relationships between the extent of inadvertent tOPV use, the time after the switch of the inadvertent tOPV use and corresponding population immunity to serotype 2 poliovirus transmission, and the ability of the inadvertently introduced viruses to cause a serotype 2 circulating vaccine-derived poliovirus (cVDPV2) outbreak in a hypothetical population. We then estimated the minimum time until inadvertent tOPV use in a supplemental immunization activity (SIA) or in routine immunization (RI) can lead to a cVDPV2 outbreak in realistic populations with properties like those of northern India, northern Pakistan and Afghanistan, northern Nigeria, and Ukraine. RESULTS At low levels of inadvertent tOPV use, the minimum time after the switch for the inadvertent use to cause a cVDPV2 outbreak decreases sharply with increasing proportions of children inadvertently receiving tOPV. The minimum times until inadvertent tOPV use in an SIA or in RI can lead to a cVDPV2 outbreak varies widely among populations, with higher basic reproduction numbers, lower tOPV-induced population immunity to serotype 2 poliovirus transmission prior to the switch, and a lower proportion of transmission occurring via the oropharyngeal route all resulting in shorter times. In populations with the lowest expected immunity to serotype 2 poliovirus transmission after the switch, inadvertent tOPV use in an SIA leads to a cVDPV2 outbreak if it occurs as soon as 9 months after the switch with 0.5 % of children aged 0-4 years inadvertently receiving tOPV, and as short as 6 months after the switch with 10-20 % of children aged 0-1 years inadvertently receiving tOPV. In the same populations, inadvertent tOPV use in RI leads to a cVDPV2 outbreak if 0.5 % of OPV RI doses given use tOPV instead of bOPV for at least 20 months after the switch, with the minimum length of use dropping to at least 9 months if inadvertent tOPV use occurs in 50 % of OPV RI doses. CONCLUSIONS Efforts to ensure timely and complete tOPV withdrawal at all levels, particularly from locations storing large amounts of tOPV, will help minimize risks associated with the tOPV-bOPV switch. Under-vaccinated populations with poor hygiene become at risk of a cVDPV2 outbreak in the event of inadvertent tOPV use the soonest after the tOPV-bOPV switch and therefore should represent priority areas to ensure tOPV withdrawal from all OPV stocks.
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Affiliation(s)
| | - Lee M Hampton
- Global Immunization Division, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
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50
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Implementation of coordinated global serotype 2 oral poliovirus vaccine cessation: risks of potential non-synchronous cessation. BMC Infect Dis 2016; 16:231. [PMID: 27230071 PMCID: PMC4880825 DOI: 10.1186/s12879-016-1536-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/04/2016] [Indexed: 11/30/2022] Open
Abstract
Background The endgame for polio eradication involves coordinated global cessation of oral poliovirus vaccine (OPV) with cessation of serotype 2 OPV (OPV2 cessation) implemented in late April and early May 2016 and cessation of serotypes 1 and 3 OPV (OPV13 cessation) currently planned for after 2018. The logistics associated with globally switching all use of trivalent OPV (tOPV) to bivalent OPV (bOPV) represent a significant undertaking, which may cause some complications, including delays that lead to different timing of the switch across shared borders. Methods Building on an integrated global model for long-term poliovirus risk management, we consider the expected vulnerability of different populations to transmission of OPV2-related polioviruses as a function of time following the switch. We explore the relationship between the net reproduction number (Rn) of OPV2 at the time of the switch and the time until OPV2-related viruses imported from countries still using OPV2 can establish transmission. We also analyze some specific situations modeled after populations at high potential risk of circulating serotype 2 vaccine-derived poliovirus (cVDPV2) outbreaks in the event of a non-synchronous switch. Results Well-implemented tOPV immunization activities prior to the tOPV to bOPV switch (i.e., tOPV intensification sufficient to prevent the creation of indigenous cVDPV2 outbreaks) lead to sufficient population immunity to transmission to cause die-out of any imported OPV2-related viruses for over 6 months after the switch in all populations in the global model. Higher Rn of OPV2 at the time of the switch reduces the time until imported OPV2-related viruses can establish transmission and increases the time during which indigenous OPV2-related viruses circulate. Modeling specific connected populations suggests a relatively low vulnerability to importations of OPV2-related viruses that could establish transmission in the context of a non-synchronous switch from tOPV to bOPV, unless the gap between switch times becomes very long (>6 months) or a high risk of indigenous cVDPV2s already exists in the importing and/or the exporting population. Conclusions Short national discrepancies in the timing of the tOPV to bOPV switch will likely not significantly increase cVDPV2 risks due to the insurance provided by tOPV intensification efforts, although the goal to coordinate national switches within the globally agreed April 17-May 1, 2016 time window minimized the risks associated with cross-border importations.
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