Keywords
Varicella vaccine
Immunization program
Epidemiological characteristics
Submitted : 2024-06-18
Accepted : 2024-07-03
Published : 2024-07-18
Abstract
Objective: To explore the changes in the epidemiological characteristics of varicella before and after implementing the two-dose varicella vaccine (VarV) immunization program in the Banan District of Chongqing and to provide a reference for future epidemic prevention and control. Methods: The data of reported varicella cases in Banan District from 2014 to 2023 were collected and analyzed using the China Disease Prevention and Control Information System. Descriptive epidemiological methods were employed to assess the changes in the reported incidence of varicella before (2014–2018) and after (2019–2023) the implementation of the two-dose VarV immunization program. Results: The average annual reported incidence rate of varicella in Banan District from 2014 to 2023 was 81.53 per 100,000. From 2014 to 2018, the reported incidence rate showed an upward trend year by year (trend χ² = 223.96, P < 0.05). However, the reported incidence rate decreased from 2019 to 2023 (trend χ² = 189.51, P < 0.05). Before and after the adjustment of the immunization program, the reported incidence rate for the 5–9 years old group was 774.62 per 100,000 and 476.98 per 100,000, respectively, with a statistically significant difference (χ² = 161.26, P < 0.05). The onset of varicella showed a bimodal distribution, with peak incidence periods in May–June and October–December. From 2014 to 2023, a total of 155,181 doses of VarV were administered in Banan District. The estimated annual vaccination rate for the first varicella vaccine (VarV1) from 2019 to 2023 was 86.28%, and for the second dose (VarV2) was 59.18%. The primary vaccination targets were the 5–9-year-old group, accounting for 64.21%. Conclusion: After implementing the two-dose VarV immunization program in Banan District, the vaccination rate increased yearly, and the reported incidence of varicella showed a downward trend. The incidence rate of varicella in children aged 5–9 years reduced significantly, but the overall downward trend for the entire population was not as pronounced. Therefore, it is necessary to increase the vaccination rate of VarV2.
References
Sui H, Lee KS, Wang M, et al., 2019, Epidemiological Characteristics of Varicella in China from 2005 to 2015. China Vaccines and Immunization, 25(2): 155–159.
Zhao H, Zheng M, Wu F, et al., 2021, Analysis of Epidemiological Characteristics of Varicella in Jiangxi Province from 2010 to 2019. Modern Preventive Medicine, 48(7): 1156–1159.
Shapro ED, Marietta V, Daina E, et al., 2011, Effectiveness of 2 Doses of Varicella Vaccine in Children. The Journal of Infectious Diseases, 203(3): 312–315.
Zeng S, Sun L, He J, et al., 2019, Analysis of the Protective Effect of Vaccination History in Varicella Public Health Emergencies. Journal of Preventive Medicine Intelligence, 35(3): 297–302.
Zhang Z, Suo L, Pan J, et al., 2021, Two-dose Varicella Vaccine Effectiveness in China: A Meta-analysis and Evidence Quality Assessment. BMC Infectious Diseases, 21(1): 543.
Hu Y, Wang Q, Deng J, et al., 2023, Epidemiological Characteristics and Management Costs of Varicella Public Health Emergencies in Chongqing from 2014 to 2021. China Vaccines and Immunization, 29(3): 280–284.
Hu H, Cao W, Shen T, et al., 2017, Meta-analysis of the Protective Effect of Varicella Vaccine in Clustered Epidemics. China Vaccines and Immunization, 23(3): 331–336.
Zhu Y, Zhu J, Cao Y, et al., 2017, Meta-analysis of the Protective Effect of Live Attenuated Varicella Vaccine in Chinese Children. Chinese Journal of Preventive Medicine, 18(8): 587–592.
Dong P, Wang M, Liu Y, 2020, Epidemiological Characteristics of Varicella in China from 2016 to 2019. China Vaccines and Immunization, 26(4): 403–406.
Chang X, Jiang Z, Liu F, et al., 2023, Analysis of Varicella Epidemic Situation and Prediction of Incidence Trend in Hunan Province from 2014 to 2021. Chinese Journal of Preventive Medicine, 24(3): 238–242.
Xu C, Wang D, Zhou W, 2022, Analysis of Spatial Characteristics of Varicella Incidence in Zhonglou District, Changzhou City, from 2017 to 2020. Jiangsu Preventive Medicine, 33(6): 705–706 + 741.
Fei J, Zhang Q, Xu Y, et al., 2022, Analysis of the Changes in Varicella Incidence in Jiading District, Shanghai, from 2016 to 2020. Health Education and Health Promotion, 17(6): 641–644.
Li X, Wei X, Zhang W, et al., 2023, Research Progress on Epidemiological Characteristics and Influencing Factors of Varicella. Disease Surveillance, 38(7): 878–883.
Liu F, Shi L, Yao Y, et al., 2023, The Impact of Varicella Vaccine Included in the Immunization Program on Its Incidence. Shanghai Preventive Medicine, 35(7): 634–638.
Qiu C, Zhao Y, Yuan X, et al., 2020, Characteristics of Varicella Incidence After Implementing a Two-dose Varicella Vaccine Immunization Program in Haidian District, Beijing. China Vaccines and Immunization, 26(6): 643–646.
Wang Q, Zhou M, Wang X, 2020, Effect of Implementing a Two-dose Varicella Vaccine Immunization Program on the Incidence of Varicella in Xicheng District, Beijing. Chinese Journal of Biologicals, 33(2): 164–168.
Gu R, Wu R, Ding S, et al., 2023, Analysis of the Impact of Free Varicella Vaccination Strategy on the Epidemiological Characteristics of Varicella in Nanjing. Occupational and Health, 39(15): 2059–2063.
Huang X, Wu W, Liang Y, et al., 2019, A Matched Case-control Study on the Protective Effect of Varicella Vaccine. Chinese Journal of Vaccines and Immunization, 25(5): 514–516.
Wang L, Lei Q, Liu Y, 2020, Analysis of Epidemiological Characteristics and Changing Trends of Varicella in Xi’an from 2009 to 2018. Clinical Medicine Research and Practice, 5(23): 13–16.
World Health Organization, 2014, Varicella and Herpes Zoster Vaccines: WHO Position Paper, June 2014. Weekly Epidemiological Record, 89(25): 265–287.
World Health Organization, 2022, Introduction of Varicella Vaccine, World Health Organization, Geneve.
Wu Q, Liu J, Wang Y, et al., 2019, Effectiveness of Second-dose Varicella Vaccination as Post-exposure Prophylaxis: A Prospective Cohort Study. Clinical Microbiology and Infection, 25(7): 872–877.
Sui H, Guo Y, Wang B, et al., 2023, Global Varicella Vaccine Immunization Strategy and Research Progress for Children. Chinese Journal of Viral Diseases, 13(4): 294–298.