COVID-19 vaccination around immune checkpoint inhibitor start and survival in a nationwide cohort of patients with cancer.

Abstract

Experimental data suggest that COVID-19 vaccination could modulate immune checkpoint inhibitor (ICI) effects, but population evidence is limited. Using the French health data system (Système National des Données de Santé), we identified 95,015 adults initiating ICI therapy between December 2020 and March 2023. We assessed mRNA vaccination within 100 days before ICI initiation using inverse probability of treatment weighting and within 100 days after ICI initiation among previously unvaccinated patients using a cloning-censoring-weighting target-trial emulation. The primary outcome was all-cause mortality; secondary outcomes were cancer-specific and non-COVID-19 mortality. Follow-up extended to 31 December 2024 for all-cause mortality and to 31 December 2023 for cause-specific deaths. Pre-ICI mRNA vaccination was associated with lower early all-cause mortality (hazard ratio (HR) 0.90 (95% confidence interval (CI) 0.87-0.94) at 1-3 months and 0.96 (0.93-1.00) at 6 months) and no significant association after 12 months. Post-ICI mRNA vaccination showed a similar early association (HR 0.84 (95% CI 0.80-0.88) at 3 months and 0.86 (0.79-0.94) at 6 months), also with no significant association after 12 months. Estimates for non-COVID-19 and cancer-specific mortality were similar to those for overall survival. Similar early patterns with non-mRNA COVID-19 and other adult vaccines suggest modest, transient associations or healthy-vaccinee effects, rather than a specific mRNA COVID-19 vaccine effect.