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Pillsbury M, Carias C, Samant S, Greenberg D, Pawaskar M. Comparison of performance of varicella vaccines via infectious disease modeling. Vaccine 2022; 40:3954-3962. [PMID: 35660037 DOI: 10.1016/j.vaccine.2022.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 04/06/2022] [Accepted: 05/03/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND Population-level infectious disease models for varicella require vaccine parameters, namely 'take' and 'duration of protection' (defined here as vaccine performance), to quantify the impact of vaccination. Current published models for varicella use vaccine parameters derived from various methodologies which does not allow for the direct comparison of different vaccines. METHODS We estimated take and duration of protection using deterministic compartmental models to simulate clinical trials of one- or two-dose varicella vaccination using Varivax® (V-MSD) and Varilrix® (V-GSK). We fit different models to clinical trial data on breakthrough infections and evaluated their respective goodness-of-fit using the Akaike Information Criterion (AIC). RESULTS Based upon the clinical trial data, we estimated that 90.3% (95% CI: 87.8-92.9%) of the cohort gained permanent protection from breakthrough varicella after the first dose of V-MSD compared to 61.7% (95% CI: 58.2-65.3%) with the first dose of V-GSK. We further estimated that a total of 97.0% (95% CI: 95.2-98.8%) and 93.8% (95% CI: 92.2-95.4%) of the cohort were permanently protected after two-doses of V-MSD and V-GSK, respectively. According to the AIC, our new model (V-MSD AIC = 92.7; V-GSK AIC = 170.3) provided a better fit than an existing model (V-MSD AIC = 108.9; V-GSK AIC = 216.1). CONCLUSIONS The model developed fits the long-term clinical trial data on breakthrough infections for both V-MSD and V-GSK, thus, allowing for the direct comparison of vaccine performance. We estimated that a single dose of V-MSD was more likely to provide permanent protection than a single dose of V-GSK, while the protection offered by two doses was similar for both vaccines.
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Affiliation(s)
- Matthew Pillsbury
- Center for Observational and Real-World Evidence (CORE), Merck & Co., Inc., Kenilworth, NJ, USA
| | - Cristina Carias
- Center for Observational and Real-World Evidence (CORE), Merck & Co., Inc., Kenilworth, NJ, USA
| | - Salome Samant
- Center for Observational and Real-World Evidence (CORE), Merck & Co., Inc., Kenilworth, NJ, USA
| | - David Greenberg
- Ben Gurion University. Division of Pediatrics, Beer-Sheva, Israel
| | - Manjiri Pawaskar
- Center for Observational and Real-World Evidence (CORE), Merck & Co., Inc., Kenilworth, NJ, USA.
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Lee T, Suh J, Choi JK, Lee J, Park SH. Estimating the basic reproductive number of varicella in South Korea incorporating social contact patterns and seroprevalence. Hum Vaccin Immunother 2021; 17:2488-2493. [PMID: 33829948 DOI: 10.1080/21645515.2021.1898917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Varicella, which is caused by the varicella zoster virus (VZV), is a common infectious disease affecting children. Varicella vaccines have been used for decades; however, vaccination policies vary across countries because of differences in VZV epidemiology. The basic reproductive number R0 a transmissibility measure parameter, also differs from country to country. In this study R0 for varicella was estimated in South Korea using the contact rate matrix derived from averaged POLYMOD contact data, the Korean population, and proportionality factor fitted to the Korean VZV seroprevalence R0 for varicella in South Korea was estimated to be 5.67 (95% CI: 5.33, 6.33). Therefore, to reach the herd immunity threshold, the critical vaccine coverage should be greater than 82.4% with a perfect vaccine, or the primary vaccine failure proportion should be less than 17.6% with 100% coverage. Because of the relatively low seroconversion rate and rapidly waning immunity after one-dose vaccination in South Korea, the herd immunity threshold is difficult to attain with only a one-dose vaccine. Two doses of vaccination may be necessary to effectively interrupt varicella transmission and maintain herd immunity in South Korea. The study results can help guide the decision-making on an effective varicella vaccination policy in South Korea.
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Affiliation(s)
- Taeyong Lee
- School of Mathematics and Computing (Mathematics), Yonsei University, Seoul, Republic of Korea
| | - Jiyeon Suh
- School of Mathematics and Computing (Computational Science and Engineering), Yonsei University, Seoul, Republic of Korea
| | - Jae-Ki Choi
- Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jeehyun Lee
- School of Mathematics and Computing (Mathematics), Yonsei University, Seoul, Republic of Korea.,School of Mathematics and Computing (Computational Science and Engineering), Yonsei University, Seoul, Republic of Korea
| | - Sun Hee Park
- Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Patić A, Štrbac M, Petrović V, Milošević V, Ristić M, Hrnjaković Cvjetković I, Medić S. Seroepidemiological study of rubella in Vojvodina, Serbia: 24 years after the introduction of the MMR vaccine in the national immunization programme. PLoS One 2020; 15:e0227413. [PMID: 31929584 PMCID: PMC6957133 DOI: 10.1371/journal.pone.0227413] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 12/18/2019] [Indexed: 11/18/2022] Open
Abstract
Although rubella is usually a mild childhood disease, this infection in early pregnancy poses a serious problem due to its teratogenic effect. The goal of interrupted circulation and elimination of rubella virus was achieved in many countries in the world. The aim of this study was to determine the status of rubella immunity in Vojvodina and evaluate Serbia's progress toward this goal. A total of 3404 residual serum samples from patients of all ages (1 to 84 years) were included in the study. Samples were collected between May 2015 and December 2017 in Vojvodina. Rubella IgG antibodies were determined using an indirect chemiluminescent immunoassay. Percentage of participants seropositive for rubella antibodies was 92.9% in the entire sample. The highest number of seronegatives was in the youngest (1 year) age group (44.7%), followed by the group aged 24-49 (6.4%) and 2-11 years (6.2%). The absence of a higher percentage of children with protective anti-rubella antibodies in the group aged 2-11 can be explained by a lower immunization coverage during certain years. Participants in the group aged 24-49 were born during the pre-vaccination period with lower rubella incidence, leading to the conclusion that not all individuals of that age came into a contact with the virus. Comparing levels of anti-rubella IgG antibodies of seropositive males and females of different ages reveals that the immunity after a contact with the virus and a previously acquired infection is stronger than the immunity after the vaccination. Although the incidence rate of rubella in Vojvodina has been low for the last ten years, there is still a risk of an outbreak due to a decrease in immunization coverage. This study shows that the percentage of susceptible individuals is high, especially considering women aged 24-49, and that additional ("catch-up") immunization is required.
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Affiliation(s)
- Aleksandra Patić
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
- Centre for Virology, Institute of Public Health of Vojvodina, Novi Sad, Serbia
- * E-mail:
| | - Mirjana Štrbac
- Centre for Disease Control and Prevention, Institute of Public Health of Vojvodina, Novi Sad, Serbia
| | - Vladimir Petrović
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
- Centre for Disease Control and Prevention, Institute of Public Health of Vojvodina, Novi Sad, Serbia
| | - Vesna Milošević
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
- Centre for Virology, Institute of Public Health of Vojvodina, Novi Sad, Serbia
| | - Mioljub Ristić
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
- Centre for Disease Control and Prevention, Institute of Public Health of Vojvodina, Novi Sad, Serbia
| | - Ivana Hrnjaković Cvjetković
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
- Centre for Virology, Institute of Public Health of Vojvodina, Novi Sad, Serbia
| | - Snežana Medić
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
- Centre for Disease Control and Prevention, Institute of Public Health of Vojvodina, Novi Sad, Serbia
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Ristić M, Milošević V, Medić S, Djekić Malbaša J, Rajčević S, Boban J, Petrović V. Sero-epidemiological study in prediction of the risk groups for measles outbreaks in Vojvodina, Serbia. PLoS One 2019; 14:e0216219. [PMID: 31071124 PMCID: PMC6508608 DOI: 10.1371/journal.pone.0216219] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 04/16/2019] [Indexed: 12/04/2022] Open
Abstract
Background Age-stratified serologic surveys provide insight into the gaps of measles-specific immunity as well as estimates of the age-specific seroprevalence. The aim of this study was to describe the measles sero-epidemiology in Vojvodina before the occurrence of outbreak in 2017/18 and to discuss preventive measures for potential future epidemics. Methods A seroprevalence study was conducted from April 2015 to June 2017 on serum bank of 3199 residual samples. Study was performed prior to the last measles outbreak in Vojvodina that occurred between 12th November 2017 and 30th June 2018. Measles-specific IgG antibodies were determined using an indirect chemiluminescent immunoassay (CLIA). Results Median age of enrolled participants was 20 years (IQR 11–37). Overall, 86.9% serum samples were seropositive. The highest proportion of measles seronegativity was observed in children aged 12–23 months of age and in adults aged 20–39 years (56.1% and 18.5%, respectively). Prevalence of measles seronegativity above WHO target levels susceptibility was observed in the following age groups: 2, 7, 13, 15, and among all adults aged between 20 and 49 years. Out of total measles outbreak cases (177), there were 91 (51.4%) participants aged 20–39 years. A significant positive correlation was observed between measles seronegativity and the number of reported measles cases aged ≥ 12 months (r = 0.4675, p = 0.0213). Conclusions In order to prevent new outbreaks and achieve the elimination of measles in Vojvodina, the vaccination coverage of both measles-mumps-rubella (MMR1 and MMR2) vaccines needs to be improved and sustained. Educational campaigns for the improvement of acceptance and timely vaccination with vaccine against measles among doctors and the general population are crucial. Our results indicate possible gap in measles protection in adults born during implementation of one dose of measles vaccine and prioritize supplementary immunization activities targeting adults in Vojvodina, Serbia.
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Affiliation(s)
- Mioljub Ristić
- University of Novi Sad, Faculty of Medicine, Department of Epidemiology, Novi Sad, Serbia
- Institute of Public Health of Vojvodina, Centre for Disease Control and Prevention, Novi Sad, Serbia
- * E-mail:
| | - Vesna Milošević
- University of Novi Sad, Faculty of Medicine, Department of Microbiology with Parasitology and Immunology, Novi Sad, Serbia
| | - Snežana Medić
- University of Novi Sad, Faculty of Medicine, Department of Epidemiology, Novi Sad, Serbia
- Institute of Public Health of Vojvodina, Centre for Disease Control and Prevention, Novi Sad, Serbia
| | - Jelena Djekić Malbaša
- University of Novi Sad, Faculty of Medicine, Department of Epidemiology, Novi Sad, Serbia
- Institute of Public Health of Vojvodina, Centre for Disease Control and Prevention, Novi Sad, Serbia
| | - Smiljana Rajčević
- University of Novi Sad, Faculty of Medicine, Department of Epidemiology, Novi Sad, Serbia
- Institute of Public Health of Vojvodina, Centre for Disease Control and Prevention, Novi Sad, Serbia
| | - Jasmina Boban
- University of Novi Sad, Faculty of Medicine, Department of Radiology, Novi Sad, Serbia
- Oncology Institute of Vojvodina, Centre for Diagnostic Imaging, Sremska Kamenica, Serbia
| | - Vladimir Petrović
- University of Novi Sad, Faculty of Medicine, Department of Epidemiology, Novi Sad, Serbia
- Institute of Public Health of Vojvodina, Centre for Disease Control and Prevention, Novi Sad, Serbia
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