Assessment of the association between mRNA COVID-19 vaccination around immunotherapy initiation and survival in patients with cancer
A nationwide study based on data from the French National Health Data System (Système National des Données de Santé, SNDS) evaluated the association between COVID-19 vaccination and survival among 95,015 adults who initiated an immune checkpoint inhibitor (ICI) between December 2020 and March 2023. Published in Nature Medicine, the study used a target trial emulation approach designed to minimize biases inherent to observational studies.
Vaccination occurring within the 100 days before or after immunotherapy initiation was considered separately. For vaccination before treatment, inverse probability of treatment weighting was used to balance baseline characteristics between vaccinated and unvaccinated groups. For vaccination after treatment initiation, a “cloning-censoring-weighting” approach was used to account for immortal time bias. The models included multiple demographic and oncological factors, comorbidities, measures of frailty, and healthcare utilization. Complementary analyses included assessments of non-COVID-19 mortality, cancer-specific mortality, real-world progression-free survival (rwPFS), analyses involving other vaccines, as well as positive and negative controls.
The analyses showed lower mortality among vaccinated patients, with a modest and transient association. As a similar association was also observed with other adult vaccines, these findings are consistent with a “healthy vaccinee effect”, that is, an association reflecting the generally better health of vaccinated individuals rather than a specific effect of COVID-19 mRNA vaccines.
This study, led by Professors Florence Tubach, Joe-Elie Salem, and Jacques Cadranel, was conducted at the AP-HP Center for Pharmacoepidemiology and involved Raphaëlle Curmin, Aya Ajrouche and Yann De Rycke from the PEPITES team at the Sorbonne Public Health Institute.