Association of mRNA COVID-19 vaccination with overall survival in patients receiving immune checkpoint inhibitors: a retrospective cohort analysis.

BackgroundA retrospective study in Nature recently reported improved overall survival (OS) when COVID-19 mRNA vaccination was administered around initiation of immune checkpoint inhibitor (ICI) therapy. Whether this association depends on vaccination timing relative to ICI treatment remains unclear. MethodsWe conducted a single-centre retrospective cohort study of patients receiving palliative-intent ICI therapy at a UK tertiary cancer centre (October 2014-December 2025). Two vaccination exposure definitions were evaluated: (1) vaccination within 100 days of the first ICI cycle (initial window); and (2) vaccination from 100 days before the first ICI cycle to 100 days after the final ICI cycle (extended window). OS was analysed using Kaplan-Meier methods and Cox models relative to unvaccinated patients. ResultsAmong 2109 patients, 515 (24.4%) received [&ge;]1 COVID-19 vaccine dose. Under the initial window, mRNA vaccination was associated with a longer OS in the all-tumours cohort only (HR 0.76; 95% CI 0.58-0.99; p=0.04). Under the extended window, mRNA vaccination was associated with longer OS in the all-tumours cohort (HR 0.58; 95% CI 0.46-0.75; p<0.0001), including melanoma (HR 0.35; 95% CI 0.18-0.69; p=0.002) and kidney cancer (HR 0.47; 95% CI 0.28-0.79; p=0.004), but not NSCLC. In an era-restricted analysis limited to patients receiving ICI therapy from 2020 onwards, the all-tumours association persisted (HR 0.76; 95% CI 0.59-0.98; p=0.04) with no significant tumour-specific associations. ConclusionsCOVID-19 mRNA vaccination was associated with improved OS, with magnitude and tumour specificity dependent on vaccination exposure definition. Prospective studies are required to assess causality and tumour-specific effects.