Long-term follow-up of production of IgM and IgG antibodies against SARS-CoV-2 among patients with COVID-19

Abstract

The patients diagnosed with coronavirus disease 2019 (COVID-19) produce IgM and IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) . However, the frequency and duration of antibody production still need to be fully understood. In the present study, we investigated the duration of antibody production after SARS-CoV-2 infection. The patients diagnosed with COVID-19 were monitored over twelve months for the production of SARS-CoV-2 IgM and IgG antibodies, and the characteristics of these patients were examined. Forty-five patients diagnosed with COVID-19 were enrolled, and thirty-four patients were followed up until they tested negative for SARS-CoV-2 IgM and IgG antibodies or up to twelve months after the date of a negative SARS-CoV-2 polymerase chain reaction (PCR) result. The positivity rates of SARS-CoV-2 IgM and IgG antibodies were 27.3％ and 68.2％ when SARS-CoV-2 PCR was negative, 20.6％ and 70.6％ after one month, 8.8％ and 52.9％ after three months, and 0.0％ and 14.7％ after six months, respectively. Moreover, we compared patients with milder conditions who did not require oxygen administration with those with severe conditions which required oxygen administration. The positivity rate of SARS-CoV-2 IgG antibodies was significantly higher in patients with severe conditions than in those with milder conditions on the date of a negative SARS-CoV-2 PCR result and after one month and three months, but not after six months. Patients with more severe COVID-19 produced more SARS-CoV-2 IgG antibodies. Moreover, it is suggested that the duration of IgG antibody production is independent of COVID-19 severity.