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Xiu S, Wang X, Wang Q, Jin H, Shen Y. Impact of implementing a free varicella vaccination policy on incidence in Wuxi City, China: an interrupted time series analysis. Epidemiol Infect 2023; 151:e125. [PMID: 37469289 PMCID: PMC10540171 DOI: 10.1017/s0950268823001152] [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: 03/08/2023] [Revised: 06/08/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023] Open
Abstract
Varicella vaccination is optional and requires self-payment. On 1 December 2018, Wuxi City launched a free varicella vaccination program for children. This study aimed to evaluate the changes in varicella incidence before and after the implementation of the policy. The data were obtained from official information systems and statistical yearbooks. We divided the period into chargeable (January 2017 to November 2018) and free (December 2018 to December 2021) periods. Interrupt time series analysis was used to conduct a generalised least-squares regression analysis for the two periods. A total of 51,071 varicella cases were reported between January 2017 and December 2021. After the implementation of the policy, there was a statistically significant decrease in the incidence of varicella (β2 = -0.140, P = 0.017), and the slope of the incidence also decreased by 0.012 (P = 0.015). Following policy implementation, the incidence decreased in all age groups, with the largest decline observed among children aged 8-14 years (β2 = -1.109, P = 0.009), followed by children aged ≤7 years (β2 = -0.894, P = 0.013). Our study found a significant reduction in the incidence of varicella in the total population after the introduction of free varicella vaccination in Wuxi City.
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Affiliation(s)
- Shixin Xiu
- Department of Immunization, Wuxi Center for Disease Control and Prevention, Wuxi, China
| | - Xuwen Wang
- Department of Immunization, Wuxi Center for Disease Control and Prevention, Wuxi, China
| | - Qiang Wang
- Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Nanjing, China
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, China
| | - Hui Jin
- Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Nanjing, China
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, China
| | - Yuan Shen
- Department of Immunization, Wuxi Center for Disease Control and Prevention, Wuxi, China
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Lee YH, Choe YJ, Hong K, Yoon Y, Kim YK. The Protective Effectiveness of 2-Dose Varicella Vaccination in Children in Korea: A Case-Control Study. Pediatr Infect Dis J 2023:00006454-990000000-00438. [PMID: 37171976 DOI: 10.1097/inf.0000000000003958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
BACKGROUND A 2-dose vaccination against varicella has been adopted in many places; however, it has not been widely introduced in Korea. This study aimed to assess 1-dose and 2-+dose vaccine effectiveness (VE) against laboratory-confirmed varicella in Korea to provide a scientific basis for developing an immunization strategy. METHODS We constructed a national cohort using national surveillance data and the national immunization registry. From the cohort, we conducted a 1:2 matched nested case-control study to estimate and compare the VE of the 1-dose and 2-dose of varicella vaccination using exact conditional logistic regression. VE was calculated as [1 - matched odds ratio (OR) × 100%]. RESULTS From January 1, 2011 to December 31, 2020, a total of 205,173 varicella cases were reported to the notifiable diseases surveillance system. Of these, we included 4,387 laboratory-confirmed varicella cases and 8,774 controls for the analyses. The VE of 1-dose vaccination was 16.8% (95% CI: -9.0% to 36.5%), whereas the VE of 2-doses of the vaccination was 98.6% (95% CI: 96.0%-99.5%). CONCLUSION These findings suggest that the 2-dose vaccination strategy can be an effective strategy to prevent varicella.
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Affiliation(s)
- Young Hwa Lee
- Allergy Immunology Center, Korea University, Seoul, Korea
| | - Young June Choe
- Department of Pediatrics, Korea University Anam Hospital, Seoul, Korea
| | - Kwan Hong
- Department of Preventive Medicine, Korea University College of Medicine
| | - Yoonsun Yoon
- Department of Pediatrics, Korea University Guro Hospital, Seoul, Korea; and
| | - Yun-Kyung Kim
- Department of Pediatrics, Korea University Ansan Hospital and Korea University College of Medicine, Seoul, Korea
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Gao Z, Yang F, Qi F, Li X, Li S. Evaluating the impact of universal varicella vaccination among preschool-aged children in Qingdao, China: An interrupted time-series analysis. Hum Vaccin Immunother 2022; 18:2094641. [PMID: 35820088 DOI: 10.1080/21645515.2022.2094641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Varicella is a contagious disease of children. Qingdao administrated free one-dose and free two-dose universal varicella vaccination schedules in 2013 and 2016 for preschool children. The effectiveness of the vaccination was analyzed in this study. Monthly varicella incidence data of 1-6 years old children during 2007-2020 were obtained from the Qingdao Infectious Disease Reporting Information Management System. We applied Interrupted time series and segmented regression analyses to assess changes in varicella incidence at the beginning of each month and average monthly changes during the vaccination. The vaccination was associated with a reduction of 32.7% in varicella morbidity on average during the 8-year intervention, there is a statistically significant difference between the voluntary period and free vaccination period (χ2 = 290.80,P < 0.001). Immediately after the free one-dose vaccination implementation in 2013 and free two-dose vaccination implementation in 2016, varicella incidence decreased by 0.135 cases per 100 000 population (P < 0.001) and increased by 1.189 cases per 100 000 population (P = 0.039), respectively, the results were statistically significant. There were significant declining trends in varicella incidence after free vaccination: 0.135(P < 0.001) and 0.055 (P = 0.025) per month in 2013.7-2016.6 and 2016.7-2020.12, respectively. This study shows a further decaying trend of varicella incidence based on the impact of free two-dose vaccination. It is necessary to prolong free two-dose universal varicella vaccination to strengthen the immune barrier of preschool children sequentially.
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Affiliation(s)
- Zheng Gao
- Department of Epidemiology and health statistics, school of public health, Qingdao University, Qingdao, China
| | - Feng Yang
- Qingdao Municipal Center for Disease Control and Prevention, Qingdao Institute of Preventive Medicine, Qingdao, China
| | - Fei Qi
- Qingdao Municipal Center for Disease Control and Prevention, Qingdao Institute of Preventive Medicine, Qingdao, China
| | - Xiaofan Li
- Qingdao Municipal Center for Disease Control and Prevention, Qingdao Institute of Preventive Medicine, Qingdao, China
| | - Shanpeng Li
- Qingdao Municipal Center for Disease Control and Prevention, Qingdao Institute of Preventive Medicine, Qingdao, China
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Shu M, Zhang D, Ma R, Yang T, Pan X. Long-term vaccine efficacy of a 2-dose varicella vaccine in China from 2011 to 2021: A retrospective observational study. Front Public Health 2022; 10:1039537. [PMID: 36424959 PMCID: PMC9679788 DOI: 10.3389/fpubh.2022.1039537] [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] [Received: 09/08/2022] [Accepted: 10/24/2022] [Indexed: 11/10/2022] Open
Abstract
Objective A 2-dose varicella vaccine immunization strategy has been implemented in many cities in China, but there is few evidence on a long-term evaluation of the efficacy of the 2-dose varicella vaccine from China. This study aims to assess the long-term vaccine efficacy of the two doses varicella vaccine and analysis of its influencing factors. Methods A retrospective study was carried out in 837,144 children born between 2011 and 2017 in Ningbo, Easten China. The logistic regression was performed to estimate varicella vaccine effectiveness (VE). Results The overall VE of 2 doses of varicella vaccine compared without the vaccine was 90.31% (89.24-91.26%), and the overall incremental VE of 2 doses of varicella vaccine compared to the 1-dose was 64.71% (59.92-68.93%). Moreover, the varicella vaccination age of the second dose and the interval between 2 doses were both associated with VE. The VE compared to that without the vaccine in children vaccinated at <4 years old was 91.22% (95%CI: 90.16-92.17%) which was higher than in children vaccinated at ≥4 years old (VE: 86.79%; 95%CI: 84.52-88.73). And the effectiveness of the vaccine was 93.60% (95%CI: 92.19-94.75%) in children with the interval of the 2 doses ≤ 24 months significantly higher than in children with the interval of ≥36 months (VE: 85.62%, 95%CI: 82.89-87.91%). Conclusions This study provides evidence for long-term VE of the 2-dose varicella vaccine and the better age for 2-dose vaccination and the interval between 2 doses of the vaccine in China.
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Affiliation(s)
- Mingming Shu
- Ningbo Women and Children's Hospital, Ningbo, China
| | - Dandan Zhang
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo, China
| | - Rui Ma
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo, China
| | - Tianchi Yang
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo, China
| | - Xingqiang Pan
- Ningbo Municipal Center for Disease Control and Prevention, Ningbo, China,*Correspondence: Xingqiang Pan
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Hoshina T, Kawase M, Watanabe S, Shibahara J, Kojiro M, Miyake T, Sakaguchi Y, Kajiwara Y, Kusuhara K. Trends in voluntary vaccination coverage in a Japanese city. Pediatr Int 2021; 63:1466-1471. [PMID: 33780596 DOI: 10.1111/ped.14712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/18/2021] [Accepted: 03/26/2021] [Indexed: 11/25/2022]
Abstract
BACKGROUND Large numbers of patients with diseases preventable by voluntary vaccines have been reported in Japan. However, it is difficult to analyze the impact of voluntary vaccination on disease prevention, as governments do not aggregate the number of recipients of vaccines that are not included in the national immunization program. This study investigated the association between the coverage rates of two voluntary vaccines (rotavirus and mumps vaccines) and the incidence of the diseases preventable by these vaccines. METHODS We performed a prospective questionnaire-based observational study to investigate the presumptive coverage rates of the rotavirus vaccine in infancy and the mumps vaccine at 1 year of age in Kitakyushu City from 2015 to 2018. The number of children admitted to a secondary medical institution for rotavirus-associated gastroenteritis and the incidence of mumps infection in sentinel medical institutions were also analyzed during the investigation period. RESULTS The rotavirus and mumps vaccine coverage rates since 2016 were 61-63% and late 28-30%, respectively (52.6% and 20.3% in 2015, respectively). The yearly number of children hospitalized for rotavirus-associated gastroenteritis from 2015 to 2018 declined by 41.4% compared with that during the pre-vaccination period (2009-2011). The incidence of mumps infection remained unchanged during the investigation period. CONCLUSION The coverage rates of two voluntary vaccines were not high enough to control the infections. The incorporation of voluntary vaccines into the routine immunization program should be considered as the one of the effective ways to increase vaccination coverage.
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Affiliation(s)
- Takayuki Hoshina
- Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan
| | - Mayumi Kawase
- Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan.,Department of Pediatrics, Kitakyushu General Hospital, Kitakyushu, Japan
| | - Shunsuke Watanabe
- Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan.,Department of Pediatrics, Kitakyushu General Hospital, Kitakyushu, Japan
| | - Junpei Shibahara
- Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan.,Department of Pediatrics, Kitakyushu General Hospital, Kitakyushu, Japan
| | - Masumi Kojiro
- Department of Pediatrics, Kitakyushu General Hospital, Kitakyushu, Japan
| | - Takumi Miyake
- Kitakyushu Society of Child Health, Kitakyushu, Japan.,Miyake Clinic, Kitakyushu, Japan
| | - Yusuke Sakaguchi
- Kitakyushu Society of Child Health, Kitakyushu, Japan.,Sakaguchi Children Clinic, Kitakyushu, Japan
| | - Yasuhiro Kajiwara
- Kitakyushu Society of Child Health, Kitakyushu, Japan.,Department of Pediatrics, Tobata General Hospital, Kitakyushu, Japan
| | - Koichi Kusuhara
- Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan
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Hong K, Sohn S, Choe YJ, Rhie K, Lee JK, Han MS, Chun BC, Choi EH. Waning Effectiveness of One-dose Universal Varicella Vaccination in Korea, 2011-2018: a Propensity Score Matched National Population Cohort. J Korean Med Sci 2021; 36:e222. [PMID: 34519184 PMCID: PMC8438188 DOI: 10.3346/jkms.2021.36.e222] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/25/2021] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Despite high coverage (~98%) of universal varicella vaccination (UVV) in the Republic of Korea since 2005, reduction in the incidence rate of varicella is not obvious. The study aimed to evaluate the vaccine effectiveness (VE) of one-dose UVV by timeline and severity of the disease. METHODS All children born in Korea in 2011 were included for this retrospective cohort study that analyzed insurance claims data from 2011-2018 and the varicella vaccination records in the immunization registry. Adjusted hazard ratios by Cox proportional hazard models were used to estimate the VE through propensity score matching by the month of birth, sex, healthcare utilization rate, and region. RESULTS Of the total 421,070 newborns in the 2011 birth cohort, 13,360 were matched for age, sex, healthcare utilization rate, and region by the propensity score matching method. A total of 55,940 (13.29%) children were diagnosed with varicella, with the incidence rate 24.2 per 1000 person-year; 13.4% of vaccinated children and 10.4% of unvaccinated children. The VE of one-dose UVV against any varicella was 86.1% (95% confidence interval [CI], 81.4-89.5) during the first year after vaccination and 49.9% (95% CI, 43.3-55.7) during the 6-year follow-up period since vaccination, resulting in a 7.2% annual decrease of VE. The overall VE for severe varicella was 66.3%. The VE of two-dose compared to one-dose was 73.4% (95% CI, 72.2-74.6). CONCLUSION We found lower long-term VE in one-dose vaccination and waning of effectiveness over time. Longer follow ups of the vaccinated children as well as appropriately designed studies are needed to establish the optimal strategy in preventing varicella in Korea.
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Affiliation(s)
- Kwan Hong
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Sangho Sohn
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Young June Choe
- Department of Pediatrics, Korea University Anam Hospital, Seoul, Korea
| | - Kyuyol Rhie
- Department of Pediatrics, Incheon Sejong Hospital, Incheon, Korea
| | - Joon Kee Lee
- Department of Pediatrics, Chungbuk National University Hospital, Cheongju, Korea
| | - Mi Seon Han
- Department of Pediatrics, Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, Korea
| | - Byung Chul Chun
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Eun Hwa Choi
- Department of Pediatrics, Seoul National University Hospital, Seoul, Korea
- Department of Pediatrics, Seoul National University Hospital, Seoul, Korea.
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Cross-Sectional Study of Varicella Zoster Virus Immunity in Healthy Korean Children Assessed by Glycoprotein Enzyme-Linked Immunosorbent Assay and Fluorescent Antibody to Membrane Antigen Test. Vaccines (Basel) 2021; 9:vaccines9050492. [PMID: 34065863 PMCID: PMC8151998 DOI: 10.3390/vaccines9050492] [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] [Received: 04/13/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 11/17/2022] Open
Abstract
The prevalence of varicella is especially high among children in the age group of 4-6 years in South Korea, regardless of vaccination. We investigated the immune status of healthy children enrolled in day-care centers and compared pre- and post-vaccination immunity. Antibody titers were measured using a glycoprotein enzyme-linked immunosorbent assay (gpEIA) kit, and the seroconversion rate was assessed using a fluorescent antibody to membrane antigen (FAMA) test. Among 541 vaccinated children, 109 (20.1%) had breakthrough varicella. However, 13 (72.2%) of the 18 unvaccinated children had a history of varicella. The gpEIA geometric mean titers (GMTs) of pre- and 5 weeks post-vaccination in 1-year-old children were 14.7 and 72 mIU/mL, respectively, and the FAMA seroconversion rate was 91.1%. The gpEIA GMTs of 2-, 3-, 4-, 5-, and 6-year-old children were 104.1, 133.8, 223.5, 364.1, and 353.0 mIU/mL, respectively. Even though the gpEIA GMT increased with age, the pattern of gpEIA titer distribution in 4- to 6-year-old vaccinees without varicella history represented both waning immunity and natural boosting immunity. These results suggest that some vaccinees are vulnerable to varicella infection. Therefore, it is necessary to consider a two-dose varicella vaccine regimen in South Korea.
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