Long-term evaluation of the seroprevalence of SARS-CoV-2 IgG and IgM antibodies in recovered patients: a meta-analysis

Estimating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) -specific immunoglobulin G (IgG) immunoglobulin M (IgM) antibodies are increasingly important for tracking the spread of infection and defining herd immunity barrier and individual immunization levels in the ongoing coronavirus disease 2019 (COVID-19) pandemic. Therefore, we conducted the present systematic review and meta-analysis to evaluate the seroprevalence of SARS-CoV-2 IgM and IgG antibodies of recovered COVID-19 patients in long-term follow-up studies. A systematic search of the MEDLINE, Embase, COVID-19 Primer, PubMed, CNKI, and the Public Health England library databases was conducted. Twenty-fourth eligible studies were included. Meta-analysis showed that 27% (95%CI: 0.04–0.49) and 66% (95%CI:0.47–0.85) were seropositive for SARS-CoV-2 IgM and IgG, respectively, while in long-term 12 months following up studies, the seroprevalences of IgM antibody (17%) decreased and IgG antibody (75%) was higher than 6 months follow-up patients. However, due to the limited number of relevant studies, the high level of heterogeneity, and the large gap in studies conducted, the findings of our study may not accurately reflect the true seroprevalence status of SARS-CoV-2 infection. Nevertheless, sequential vaccination or booster immunization is considered to be a necessary long-term strategy to sustain the fight against the pandemic.