COVID-19 vaccines weaker in kidney transplant recipients

Allograft recipients show poor immunological response to SARS-CoV-2 vaccination compared with the general population, a recent study has found.

Researchers enrolled 373 consecutive adult kidney transplant recipients who had also received two doses of the Pfizer-BioNTech (72 percent) or Oxford-AstraZeneca (28 percent) vaccines. Those who had had SARS-CoV-2 infections before, or otherwise showed antibody responses to the virus prior to vaccination, were ineligible for analysis.

Subsequent testing for antibody response through appropriate immunoassays, performed a median of 38 days after the second dose, showed that only 212 participants were positive for anti-SARS-CoV-2 antibodies. The corresponding overall seropositivity rate was 56.8 percent; the remaining 43.2 percent were classified as seronegative.

Baseline characteristics were generally comparable between patient groups, except for age (mean, 51 vs 58; p<0.001) and cardiovascular disease prevalence (20.3 percent vs 30.4 percent; p=0.024), both of which were significantly lower in seropositive patients.

Multivariate regression analysis confirmed that increasing age was a significant negative predictor of vaccine response (odds ratio [OR] per 10-year increase in age, 0.61, 95 percent confidence interval [CI], 0.01–0.11; p<0.001). Meanwhile, high estimated glomerular filtration rate correlated with better odds of vaccine response (OR per 10-mL/min/1.73 m², 1.40, 95 percent CI, 1.19–1.66; p<0.001).

Notably, of all factors assessed, the researchers found immunosuppression with mycophenolic acid as having the strongest influence on seropositivity, decreasing such likelihood by 98 percent (OR, 0.02, 95 percent CI, 0.01–0.11; p<0.001).