A community-based serological cohort study on incidence of seasonal influenza virus infection in Macheng city from winter 2019 to spring 2020
10.3760/cma.j.cn112866-20231229-00082
- VernacularTitle:2019—2020年冬春季麻城市社区季节性流感病毒感染率血清学队列研究
- Author:
Jinsong FAN
1
;
Jianbo ZHAN
;
Yue CHEN
;
Shaobo DONG
;
Jian LU
;
Junfeng GUO
;
Xiaojing LIN
;
Yu LAN
;
Kun QIN
;
Jianfang ZHOU
;
Bing HU
;
Cuiling XU
Author Information
1. 中国疾病预防控制中心病毒病预防控制所，北京 102206
- Keywords:
Seasonal influenza;
Cohort study;
Hemagglutination inhibition test;
Antibody titer
- From:
Chinese Journal of Experimental and Clinical Virology
2024;38(3):311-318
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To determine incidence of seasonal influenza virus infection in the community and to analyze the factors influencing seasonal influenza virus infection.Methods:This study recruited residents aged 6-59 years to build a cohort in 15 villages/streets in Macheng city in November 2019. Meanwhile, a cross-sectional baseline survey was conducted immediately to collect sera, information on demographics and child protection knowledge, behaviors, as well as attitudes using a questionnaire from the participants enrolled in the cohort (i.e., before the influenza epidemic season). In July 2020, a cross-sectional follow-up survey was conducted to collect sera once again (i.e., after the influenza season). Paired sera from the two cross-sectional surveys were tested for influenza virus-specific antibodies by hemagglutination inhibition (HI) test or micro-neutralization (MN) test using a circulating representative strain of each subtype/lineage of influenza virus as the test antigen. The infections with influenza virus subtype/lineage was confirmed if there was a four-fold or more increase in titers of antibodies against circulating representative strain of the subtype/lineage of influenza virus. Factors influencing infection with influenza A (H3N2) and B/Victoria viruses were analyzed using univariable and multivariable logistic regression.Results:In November 2019, 800 study participants were enrolled in the cohort, including 340 children aged 6-17 years and 460 adults aged 18-59 years; 605 study participants (including 224 children and 381 adults) were followed up in July 2020 and their paired sera were obtained before and after the influenza season. 25.3% (153/605) of the participants were confirmed to be infected with at least one subtype/lineage of seasonal influenza virus by HI and MN tests. The overall incidence of influenza viruses of all subtypes/lineages in children was 44.2% (95% CI: 37.6%-50.8%) which was significantly higher than the incidence of 14.1% in adults (95% CI: 10.7%-17.7%). Children had the highest incidence of influenza A (H3N2) virus infection, followed by B/Victoria. MN or HI antibody titers in A (H3N2)[ OR=0.88 (95% CI: 0.84-0.93)] and B/Victoria[ OR=0.97 (95% CI: 0.95-0.99)] before the influenza season were significantly associated with whether children were infected with that subtype/lineage of influenza virus. Conclusions:The residents aged 6-59 years in Macheng city had a substantial incidence of seasonal influenza virus infection during the influenza season from winter 2019 to spring 2020. Notably, almost half of children aged 6-17 years have been infected with seasonal influenza virus. Higher titers of HI/MN antibodies against seasonal influenza virus before the influenza season would be likely to reduce the risk of infection with influenza A (H3N2) and B/Victoria.
