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Programme costs for introducing age/gestation-based universal influenza vaccine schedules for young children and pregnant women in Hong Kong. Vaccine 2021; 39:6762-6780. [PMID: 34743828 DOI: 10.1016/j.vaccine.2021.10.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 10/03/2021] [Accepted: 10/06/2021] [Indexed: 01/27/2023]
Abstract
BACKGROUND Hong Kong experiences year-round influenza activity with winter and summer peaks. The government's Vaccination Subsidy Scheme (VSS) provides vaccine to high-risk groups prior to the larger winter peak. The VSS is predominantly administered through the private sector. This study aimed to cost the two theoretical routine influenza vaccination schedules using both northern and southern hemisphere vaccines, administered according to child's age and women's gestation, from a governmental perspective; and compare these costs to the costs of government's seasonal VSS assuming equivalent coverage estimates to determine the budget impacts of these influenza vaccination programmes in Hong Kong. METHODS We used the World Health Organization's Flutool Plus to estimate the incremental annual costs for immunising young children aged 6 months to 2 years and pregnant women with influenza vaccine during 2021, assuming the latter group accesses the public system for some antenatal care. Inputs were based on literature review, publicly available data and expert opinions. Sensitivity analyses were done with various coverage rates and vaccine costs. RESULTS The annual incremental cost (including vaccine price) to vaccinate young children with three doses of influenza vaccine during the first two years of life was estimated at USD 1,175,146 (per-dose-cost of USD 10.55) at 75% coverage while that to vaccinate pregnant women with one dose at 60% coverage was estimated at USD 398,555 (per-dose-cost of USD 13.39). Across a range of sensitivity analyses we predict that routine year-round schedules could be cost-saving to the government compared to the VSS. Implementing routine immunisation to both risk groups equates to USD 1,573,701, i.e., 0.012% of Hong Kong's annual healthcare spending. CONCLUSION Proposed year-round universal schedules providing influenza immunisation according to the child's age or the woman's gestation are predicted to be cost-saving compared to the current seasonally administered subsidised vaccine programme.
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Dang TKNS, Rivero Cabrera R, Yeung KHT, van der Putten IM, Nelson EAS. Feasibility of age- and gestation-based routine universal influenza vaccines schedules for children aged 6 months - 2 years and pregnant women. Vaccine 2021; 39:6754-6761. [PMID: 34674893 DOI: 10.1016/j.vaccine.2021.09.076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Hong Kong's seasonal influenza schedule follows the World Health Organization's northern hemisphere vaccine composition recommendations but with year-round influenza activity there is the potential to implement routine age- and gestation-based schedules utilising both northern and southern hemisphere vaccines for children aged 6 months to 2 years and for pregnant women. This study assessed the potential feasibility of such schedules. METHODS A literature review was conducted and in-depth interviews with vaccine experts, policy makers and nurses were undertaken. RESULTS The following schedules were proposed and assessed for perceived feasibility: 1) a four-dose schedule in the first two years of life requiring an additional unscheduled clinic visit at 7 months; 2) a three-dose schedule excluding the 4-week booster after the first dose; 3) a two-dose schedule for pregnant women involving a dose at the booking visit and a dose with pertussis vaccine at 7 months gestation; and 4) a one-dose schedule at 7 months gestation. CONCLUSIONS Age- and gestation-based routine influenza vaccination schedules are theoretically feasible for both young children and pregnant women. The three-dose paediatric and one-dose obstetric schedules were assessed in interviews with vaccine experts, policy makers and nurses to be most acceptable. Further clinical studies are required to determine whether such schedules are non-inferior to current seasonal-based schedules in terms of vaccine effectiveness and vaccine uptake.
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Affiliation(s)
- T K N Sandra Dang
- CAPHRI, Care and Public Health Research Institute, Department of Health Services Research, Maastricht University, Maastricht, the Netherlands.
| | - Romén Rivero Cabrera
- CAPHRI, Care and Public Health Research Institute, Department of Health Services Research, Maastricht University, Maastricht, the Netherlands.
| | | | - Ingeborg M van der Putten
- CAPHRI, Care and Public Health Research Institute, Department of Health Services Research, Maastricht University, Maastricht, the Netherlands.
| | - E Anthony S Nelson
- Department of Paediatrics, The Chinese University of Hong Kong, Hong Kong.
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Influenza vaccine effectiveness against influenza-associated hospitalization in children: A systematic review and meta-analysis. Vaccine 2020; 38:2893-2903. [PMID: 32113808 DOI: 10.1016/j.vaccine.2020.02.049] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 02/12/2020] [Accepted: 02/15/2020] [Indexed: 01/20/2023]
Abstract
Vaccination remains the most effective way to prevent influenza infection, albeit vaccine effectiveness (VE) varies by year. Compared to other age groups, children and elderly adults have the highest risk of developing influenza-related complications and requiring hospitalization. During the last years, "test negative design" (TND) studies have been implemented in order to estimate influenza VE. The aim of this systematic review and meta-analysis was to summarize the findings of TND studies reporting influenza VE against laboratory-confirmed influenza-related hospitalization in children aged 6 months to 17 years. We searched the PubMed and Embase databases and identified 2615 non-duplicate studies that required detailed review. Among them, 28 met our inclusion criteria and we performed a random-effects meta-analysis using adjusted VE estimates. In our primary analysis, influenza vaccine offered significant protection against any type influenza-related hospitalization (57.48%; 95% CI 49.46-65.49). When we examined influenza VE per type and strain, VE was higher against H1N1 (74.07%; 95% CI: 54.85-93.30) and influenza B (50.87%; 95% CI: 41.75-59.98), and moderate against H3N2 (40.77%; 95% CI: 25.65-55.89). Notably, influenza vaccination offered higher protection in children who were fully vaccinated (61.79%; 95% CI: 54.45-69.13), compared to those who were partially vaccinated (33.91%; 95% CI: 21.12 - 46.69). Also, influenza VE was high in children less than 5 years old (61.71%; 95% CI: 49.29-74.12) as well as in children 6-17 years old (54.37%; 95% CI: 35.14-73.60). In conclusion, in the pediatric population, influenza vaccination offered significant protection against influenza-related hospitalization and complete annual vaccination should be encouraged.
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Chua H, Feng S, Lewnard JA, Sullivan SG, Blyth CC, Lipsitch M, Cowling BJ. The Use of Test-negative Controls to Monitor Vaccine Effectiveness: A Systematic Review of Methodology. Epidemiology 2020; 31:43-64. [PMID: 31609860 PMCID: PMC6888869 DOI: 10.1097/ede.0000000000001116] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The test-negative design is an increasingly popular approach for estimating vaccine effectiveness (VE) due to its efficiency. This review aims to examine published test-negative design studies of VE and to explore similarities and differences in methodological choices for different diseases and vaccines. METHODS We conducted a systematic search on PubMed, Web of Science, and Medline, for studies reporting the effectiveness of any vaccines using a test-negative design. We screened titles and abstracts and reviewed full texts to identify relevant articles. We created a standardized form for each included article to extract information on the pathogen of interest, vaccine(s) being evaluated, study setting, clinical case definition, choices of cases and controls, and statistical approaches used to estimate VE. RESULTS We identified a total of 348 articles, including studies on VE against influenza virus (n = 253), rotavirus (n = 48), pneumococcus (n = 24), and nine other pathogens. Clinical case definitions used to enroll patients were similar by pathogens of interest but the sets of symptoms that defined them varied substantially. Controls could be those testing negative for the pathogen of interest, those testing positive for nonvaccine type of the pathogen of interest, or a subset of those testing positive for alternative pathogens. Most studies controlled for age, calendar time, and comorbidities. CONCLUSIONS Our review highlights similarities and differences in the application of the test-negative design that deserve further examination. If vaccination reduces disease severity in breakthrough infections, particular care must be taken in interpreting vaccine effectiveness estimates from test-negative design studies.
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Affiliation(s)
- Huiying Chua
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Shuo Feng
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Joseph A Lewnard
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA
| | - Sheena G Sullivan
- WHO Collaborating Centre for Reference and Research on Influenza, Royal Melbourne Hospital, and Doherty Department, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher C Blyth
- Division of Paediatrics, School of Medicine, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, Western Australia, Australia
- Department of Infectious Diseases, Perth Children's Hospital, Perth, Western Australia, Australia
| | - Marc Lipsitch
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA
- Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, Boston, MA
| | - Benjamin J Cowling
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
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Chua H, Chiu SS, Chan ELY, Feng S, Kwan MYW, Wong JSC, Peiris JSM, Cowling BJ. Effectiveness of Partial and Full Influenza Vaccination Among Children Aged <9 Years in Hong Kong, 2011-2019. J Infect Dis 2019; 220:1568-1576. [PMID: 31290537 PMCID: PMC6782104 DOI: 10.1093/infdis/jiz361] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/09/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Two doses of influenza vaccination are recommended for previously unvaccinated children aged <9 years, and receipt of 1 dose is sometimes termed "partial vaccination." We assessed the effectiveness of partial and full influenza vaccination in preventing influenza-associated hospitalization among children in Hong Kong. METHODS Using the test-negative design we enrolled 23 187 children aged <9 years admitted to hospitals with acute respiratory illness from September 2011 through March 2019. Vaccination and influenza status were recorded. Fully vaccinated children included those vaccinated with 2 doses or, if previously vaccinated, those vaccinated with 1 dose. Partially vaccinated children included those who should have received 2 doses but only received 1 dose. We estimated vaccine effectiveness (VE) by using conditional logistic regression models matched on epidemiological week. RESULTS Overall VE estimates among fully and partially vaccinated children were 73% (95% confidence interval, 69%-77%) and 31% (95% confidence interval, 8%-48%), respectively. A consistently higher VE was observed in children fully vaccinated against each influenza virus type/subtype. The effectiveness of partial vaccination did not vary by age group. CONCLUSIONS Partial vaccination was significantly less effective than full vaccination. Our study supports the current recommendation of 2 doses of influenza vaccination in previously unvaccinated children <9 years of age.
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Affiliation(s)
- Huiying Chua
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Susan S Chiu
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Eunice L Y Chan
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Shuo Feng
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Mike Y W Kwan
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong Special Administrative Region, China
| | - Joshua S C Wong
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong Special Administrative Region, China
| | - J S Malik Peiris
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Benjamin J Cowling
- World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
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Puig-Barberà J, Mira-Iglesias A, Burtseva E, Cowling BJ, Serhat U, Ruiz-Palacios GM, Launay O, Kyncl J, Koul P, Siqueira MM, Sominina A. Influenza epidemiology and influenza vaccine effectiveness during the 2015-2016 season: results from the Global Influenza Hospital Surveillance Network. BMC Infect Dis 2019; 19:415. [PMID: 31088481 PMCID: PMC6518734 DOI: 10.1186/s12879-019-4017-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/24/2019] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The Global Influenza Hospital Surveillance Network is an international platform whose primary objective is to study severe cases of influenza requiring hospitalization. METHODS During the 2015-2016 influenza season, 11 sites in the Global Influenza Hospital Surveillance Network in nine countries (Russian Federation, Czech Republic, Turkey, France, China, Spain, Mexico, India, and Brazil) participated in a prospective, active-surveillance, hospital-based epidemiological study. Influenza infection was confirmed by reverse transcription-polymerase chain reaction. Influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza was estimated using a test-negative approach. RESULTS 9882 patients with laboratory results were included of which 2415 (24.4%) were positive for influenza, including 1415 (14.3%) for A(H1N1)pdm09, 235 (2.4%) for A(H3N2), 180 (1.8%) for A not subtyped, 45 (0.5%) for B/Yamagata-lineage, 532 (5.4%) for B/Victoria-lineage, and 33 (0.3%) for B not subtyped. Of included admissions, 39% were < 5 years of age and 67% had no underlying conditions. The odds of being admitted with influenza were higher among pregnant than non-pregnant women (odds ratio, 2.82 [95% confidence interval (CI), 1.90 to 4.19]). Adjusted IVE against influenza-related hospitalization was 16.3% (95% CI, 0.4 to 29.7). Among patients targeted for influenza vaccination, adjusted IVE against hospital admission with influenza was 16.2% (95% CI, - 3.6 to 32.2) overall, 23.0% (95% CI, - 3.3 to 42.6) against A(H1N1)pdm09, and - 25.6% (95% CI, - 86.3 to 15.4) against B/Victoria lineage. CONCLUSIONS The 2015-2016 influenza season was dominated by A(H1N1)pdm09 and B/Victoria-lineage. Hospitalization with influenza often occurred in healthy and young individuals, and pregnant women were at increased risk of influenza-related hospitalization. Influenza vaccines provided low to moderate protection against hospitalization with influenza and no protection against the predominant circulating B lineage, highlighting the need for more effective and broader influenza vaccines.
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Affiliation(s)
- Joan Puig-Barberà
- Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana, FISABIO, Valencia, Spain.
| | - Ainara Mira-Iglesias
- Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana, FISABIO, Valencia, Spain
| | - Elena Burtseva
- Ivanovsky Institute of Virology FSBI "N.F, Gamaleya NRCEM" Ministry of Health, Moscow, Russian Federation
| | - Benjamin J Cowling
- School of Public Health, Li Ka Shing Faculty of Medicine, Hong Kong, Hong Kong, Special Administrative Region of China
| | - Unal Serhat
- Turkish Society of Internal Medicine, Ankara, Turkey
| | - Guillermo Miguel Ruiz-Palacios
- Salvador Zubirán National Institute of Medical Sciences and Nutrition (INCMNSZ), Vasco de Quiroga 15, Belisario Domínguez Sección 16, 14080, Tlalpan, CDMX, Mexico
| | - Odile Launay
- INSERM, F-CRIN, Réseau National d'Investigation Clinique en Vaccinologie (I-REIVAC), CIC Cochin Pasteur, Paris, France and Université Paris Descartes, Sorbonne Paris Cité and Assistance Publique Hôpitaux de Paris, Hôpital Cochin, Paris, France
| | - Jan Kyncl
- National Institute of Public Health, Prague, Czech Republic
| | - Parvaiz Koul
- Department of Internal and Pulmonary Medicine, Sher-i-Kashmir Institute of Medical Sciences (SKIMS), Soura, Bemina, Srinagar, Jammu & Kashmir, 190011, India
| | | | - Anna Sominina
- Research Institute of Influenza, WHO National Influenza Centre of Russia and Ministry of Healthcare of the Russian Federation, St. Petersburg, Russian Federation
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Yeung KHT, Tarrant M, Chan KCC, Tam WH, Nelson EAS. Increasing influenza vaccine uptake in children: A randomised controlled trial. Vaccine 2018; 36:5524-5535. [PMID: 30078745 DOI: 10.1016/j.vaccine.2018.07.066] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 07/19/2018] [Accepted: 07/24/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND Influenza vaccine is not included in the Hong Kong Government's universal Childhood Immunisation Programme but eligible children can receive subsidised vaccine through the private sector using the Vaccination Subsidy Scheme (VSS). This study examined whether a simple intervention package can increase influenza vaccine uptake in Hong Kong children. METHODS Two study samples were enrolled: families of children who had participated in a previous knowledge, attitudes and practices study; and mother-infant pairs recruited from postnatal wards. Control groups received publicly available leaflets about VSS. Intervention groups additionally received: (1) a concise information sheet about influenza and its vaccine; (2) semi-completed forms to utilise the subsidy; (3) contacts of VSS clinics that did not charge above the subsidy; and (4) text message reminders for vaccination. Enrolled mothers were contacted when children were approximately 1 and 2 years old to determine influenza vaccination status of the families and their plan to vaccinate their children. Mothers' attitudes towards influenza vaccine were assessed at enrolment and at the end of the study. RESULTS A total of 833 eligible mother-infant pairs were enrolled from the two samples. The intervention package improved influenza vaccine uptake by 22% at one year and 25% at two years of age. Maternal influenza vaccine uptake in intervention group was higher during this two-year period in those who had never been previously vaccinated. Mothers' self-efficacy regarding the use of influenza vaccine in her child i.e. belief and confidence in her own ability to make a good decision, was also improved with the intervention. CONCLUSIONS A four-component intervention package could improve influenza vaccine uptake in Hong Kong children and their mothers during the first two years of life and depending on vaccine effectiveness could potentially reduce influenza-associated hospital admissions in children below 2 years old by 13-24%.
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Affiliation(s)
- Karene Hoi Ting Yeung
- Department of Paediatrics, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - Marie Tarrant
- School of Nursing, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Kate Ching Ching Chan
- Department of Paediatrics, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - Wing Hung Tam
- Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - E Anthony S Nelson
- Department of Paediatrics, The Chinese University of Hong Kong, Hong Kong Special Administrative Region.
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