Vaccination and COVID-19 dynamics in hemodialysis patients: a population-based study in France.

Abstract Importance Maintenance hemodialysis (MHD) patients have a high mortality risk after COVID-19 and an altered humoral response to vaccines, but vaccine clinical efficacy remains unknown in this population. Objective To estimate the association between vaccination and COVID-19 hospitalization rate in MHD patients Design Using Bayesian multivariable spatiotemporal models, we estimated the expected number of SARS-CoV-2 severe infections (infections with hospital admission) in MHD patients from simultaneous cases in the general population. Setting French population-based retrospective analysis in MHD and non-dialysis patients. Participants Models were fitted from 3620 hospitalizations of MHD patients and 457,160 hospitalizations in the general population. Exposure Severe SARS-CoV-2 infections in the general population and vaccine exposure. Main Outcome and Measure Weekly incidence of severe infections in MHD patients. Results During the first epidemic wave, incidence of severe infections in MHD patients was approximately proportional to incidence in the general population. However, our model overestimated incidence during the second wave, suggesting an effect of prevention measures during the 2nd wave. A second model (based on data up to the end of the 2nd wave) estimated that the risk in MHD patients decreased between waves 1 and 2, with incidence rate ratio (IRR) = 0.70 (95% CI: 0.64, 0.76). Moreover, while this model correctly estimated the reported MHD cases up to the end of the 2nd wave, predictions overestimated the expected number of cases from the beginning of the vaccination campaign. Using vaccination coverages as additional predictors permitted to correctly fit the weekly reported number of cases, with IRR in MHD patients of 0.41 (95% CI: 0.28, 0.58) for vaccine exposure in MHD patients and 0.50 (95% CI: 0.40, 0.61) per 10% increase in vaccination coverage in the same-age general population. Conclusions and Relevance Our findings suggest that both individual and herd immunity due to vaccination may yield a protective effect against severe forms of COVID-19 in MHD patients. Question Whether vaccination against SARS-CoV-2 limits hospitalization rates in hemodialysis patients is still unknown. Findings By modeling the dynamics of 3620 hospital admissions for SARS-CoV-2 infections among hemodialysis patients, as a proportion of 457,160 cases reported in the French general population from March 2020 to April 2021, we identified vaccination coverage in both hemodialysis patients and the general population as independently associated with protection of hemodialysis patients against severe infection. Meaning Vaccination against SARS-CoV-2 is associated with reduced hospitalization rate in hemodialysis patients.