What is the time of seroconversion and duration of IgM and
IgG responses against SARS-CoV-2?
From previous SARS studies, it is known that the median seroconversion
time for detectable IgG was 17 days after infection.31Detectable levels of SARS-specific IgG and neutralizing antibodies
persisted for up to 720 days. This suggests that there is
antibody-mediated protection from SARS-CoV recurrent infection for up to
2 years.32 There are inconsistent reports on the
humoral response to SARS-CoV-2. One study with 285 COVID-19 patients
reported that SARS-CoV-2 virus-specific IgG and IgM peaked 17–19 days
and 20–22 days after symptom onset, respectively.33On the other hand, another study of 26 hospitalized COVID-19 patients
showed that seroconversion could take up to 50 days.34These discrepancies may be related to the time of SARS-CoV-2 diagnosis
or the clinical characteristics of each cohort and warrant additional
studies.