Morning administration enhances humoral response to SARS-CoV-2 vaccination in kidney transplant recipients

Although SARS-CoV-2 mRNA vaccines are effective in kidney transplant recipients (KTRs), their immune response to vaccination is blunted by immunosuppression. Other tools enhancing vaccination response are therefore needed. Interestingly, aligning vaccine administration with circadian rhythms (chronovaccination) was shown to boost immune response. However, its applicability in KTRs, whose circadian rhythms are likely disrupted by immunosuppressants, remains unclear. To assess the impact of vaccination timing on seroconversion in KTRs population, we analyzed data from 553 virus-naïve KTRs who received two doses of mRNA vaccines. Bayesian logistic regression was employed, adjusting for previously identified predictors of seroconversion, including allograft function, maintenance immunosuppressants, or time since transplantation. SARS-CoV-2 IgG antibody levels were measured with a median of 47 days after the second dose. Results did not reveal a reliable effect of timing of the first dose but did indicate that earlier timing for the second dose brings a notable benefit - every one-hour delay in the application was associated with a 16% reduction in the odds of seroconversion (OR 0.84, 95% CI 0.71, 0.998). Similar results were obtained from quantile regression modeling IgG levels. In conclusion, morning vaccination is emerging as a promising and easily implementable strategy to enhance vaccine response in KTRs.