Greater disease severity was independently associated with persistent antibody level, and patients with milder disease appeared to have more rapid antibody waning.
By contrast, T-cell responses seem to have no clear correlation with the different patterns of antibody dynamics. Patients from all groups, including the negative group, showed sustained T-cell immunity 6 months after initial infection.
By modelling the rate of antibody waning in different groups, we were able to establish prediction models to estimate the longevity of responses in individuals in the three groups showing different antibody waning rates.
In conclusion, our study showed that antibody dynamics vary greatly among individual patients with COVID-19, in peak antibody level and rate of waning and longevity of antibodies. We found an association between persistent antibodies and severe COVID-19 clinical symptoms and higher levels of pro-inflammatory cytokines and chemokines.
