Longevity of anti-spike and anti-nucleocapsid antibodies after COVID-19 in solid organ transplant recipients compared to immunocompetent controls.

Solid organ transplant recipients (SOTRs) are on lifelong immunosuppression, which may interfere with adaptive immunity to COVID-19. The data on dynamics and duration of antibody response in SOTRs are limited. This longitudinal study examined the longevity of both anti-spike (S)- and anti-nucleocapsid (N)-specific IgG-antibodies after COVID-19 in SOTRs compared to matched immunocompetent persons. SOTRs (n=65) were matched with controls (n=65) for COVID-19 disease severity, age, and sex in order of priority. Serum-IgG-antibodies against N- and S-antigens of SARS-CoV-2 were analyzed. At 1 and 9 months after COVID-19, anti-S-IgG detectability decreased from 91% to 82% in SOTRs versus 100% to 95% in controls, whereas the anti-N-IgG decreased from 63% to 29% in SOTRs versus 89% to 46% in controls. A matched paired analysis showed SOTRs having significantly lower levels of anti-N-IgG at all time points (1-month P=0.007, 3-months P<0.001, 6-months P=0.019 and 9-months P=0.021) but not anti-S-IgG at any time points. A mixed-model analysis confirmed these findings except for anti-S-IgG at one month (p=0.005) and identified severity score as the most important predictor of antibody response. SOTRs mount comparable S-specific, but not N-specific, antibody responses to SARS-CoV-2 infection compared to immunocompetent controls.