ABSTRACT
Background To investigate the anti-spike antibody response to vaccination in Kidney transplant recipients (KTRs) previously infected with SARS-CoV-2 as compared to KTRs with no history of COVID-19 from India. Methods SARS-CoV-2 spike immunoglobulin (Ig) G antibody response was measured in 105 post COVID-19 KTRs with PCR confirmed SARS-CoV-2 infection who received either no vaccination (cohort 1), single (cohort 2) or two doses (cohort 3) of vaccine and compared to 103 two-dose vaccinated COVID-19 naïve KTRs with no history of COVID-19 (cohort 4). Results Out of 103 COVID-19 naïve two-dose vaccinated KTRs, less than 50% became seropositive with anti-spike antibody titres > 50AU/mL subsequent to complete vaccination, the seroconversion rate being comparable in subjects receiving CovishieldTM versus CovaxinTM vaccines. However, the seropositive KTRs vaccinated with CovishieldTM had higher anti-spike antibody titres as compared to those who received CovaxinTM. We observed higher anti-SARS-CoV-2 spike antibody levels in post COVID-19 KTRs after 1 dose of vaccine as compared with COVID-19 naïve two-dose vaccinated KTRs. Importantly, the second dose in post COVID-19 KTRs did not significantly increase anti-spike antibody levels compared with the single dose recipients. Conclusions Our data presents that in KTRs with previous SARS-CoV-2 infection a single dose of vaccine (CovishieldTM) may be effective in mounting optimal immune response. In contrast, COVID-19 naïve two-dose vaccinated KTRs respond poorly (<50%) to current recommendation of a two-dose regimen in India.