The duration of antibody responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an area of extensive research in light of the new approvals of vaccines against SARS-CoV-2 and the use of convalescent plasma for patients with coronavirus disease 2019 (COVID-19) [1-4]. Production of anti-SARS-CoV-2 antibodies is observed in almost all symptomatic patients with COVID-19 and the elevated titers correlate with the severity of the symptoms [5-9]. Several observational studies have reported that asymptomatic individuals have also developed anti-SARS-CoV-2 antibodies [10-13].
