AUTHOR=Zhou Lijun , Li Cheng , Yang Huiping , Yuan Heng , Pan Ming , Cheng Xiuwei , Xiao Chongkun , Su Xiaoyan , Zhu Yuanfang , Xu Jianan , Tang Jianxiang , Du Xunbo , Peng Huanwen , Chen Xiao , Huang Tao , Liao Hongxiu , Xian Deqiang , Wang HaoZhou , Liu Wenwu , Zhou Ping , Zhang Zhengdong , Liu Juan , Wu Xianping , Zhang Tao
TITLE=SARS-CoV-2 Seroprevalence and Profiles Among Convalescents in Sichuan Province, China
JOURNAL=Frontiers in Public Health
VOLUME=9
YEAR=2021
URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.716483
DOI=10.3389/fpubh.2021.716483
ISSN=2296-2565
ABSTRACT=Objectives: To explore and understand the SARS-CoV-2 seroprevalence of convalescents, the association between antibody levels and demographic factors, and the seroepidemiology of convalescents of COVID-19 till March 2021.
Methods: We recruited 517 voluntary COVID-19 convalescents in Sichuan Province and collected 1,707 serum samples till March 2021. Then we reported the seroprevalence and analyzed the associated factors.
Results: Recent travel history was associated with IgM levels. Convalescents who had recent travel history were less likely to be IgM antibody negative [OR = 0.232, 95% CI: (0.128, 0.420)]. Asymptomatic cases had, approximately, twice the odds of being IgM antibody negative compared with symptomatic cases [OR = 2.583, 95% CI: (1.554, 4.293)]. Participants without symptoms were less likely to be IgG seronegative than those with symptoms [OR = 0.511, 95% CI: (0.293, 0.891)]. Convalescents aged 40–59 were less likely to be IgG seronegative than those aged below 20 [OR = 0.364, 95% CI: (0.138, 0.959)]. The duration of positive IgM antibodies persisted 365 days while the IgG persisted more than 399 days.
Conclusions: Our findings suggested that recent travel history might be associated with the antibody levels of IgM, while age could be associated with the antibody levels of IgG. Infection type could be associated with both antibody levels of IgM and IgG that declined quicker in asymptomatic cases.