Factors associated with timely COVID-19 vaccination in a population-based cohort of patients with cancer

Background — In many jurisdictions, cancer patients were prioritized for COVID-19 vaccination due to increased risk of infection and death. To understand sociodemographic disparities which impacted timely receipt of COVID-19 vaccination amongst cancer patients, we undertook a population-based study in Ontario, Canada.

Methods — Patients >18 years, diagnosed with cancer 01/2010- 09/2020 were identified using administrative data; vaccination administration was captured between approval (12/2020) up to 02/2022. Factors associated with time to vaccination were evaluated using multivariable Cox proportional hazards regression.

Results — The cohort consisted of 356,535 patients, majority of whom had solid tumor cancers (85.9%) and were not on active treatment (74.1%); 86.8% had received at least two doses. Rate of vaccination was 25% lower in recent (HR: 0.74,95% CI: 0.72-0.76) and non-recent immigrants (HR: 0.80, 95% CI: 0.79-0.81). A greater proportion of unvaccinated patients were from neighborhoods with high concentration of new immigrants or self-reported members of racialized groups (26.0% vs 21.3%, standardized difference: 0.111, P < 0.01), Residential Instability (27.1% vs 23.0%, standardized difference: 0.094, P < 0.01) or Material Deprivation (22.1% vs 16.8%, standardized difference: 0.134, P < 0.01), and low socioeconomic status (20.9% vs 16.0%, standardized difference: 0.041, P < 0.01). Rate of vaccination was 20% lower in patients from neighborhoods with the lowest socioeconomic status (HR: 0.82, 95% CI: 0.81-0.84) and highest material deprivation (HR: 0.80, 95% CI: 0.78-0.81) relative to those in more advantaged neighborhoods.

Conclusion — Despite funding of vaccines and prioritization of high-risk populations, marginalized patients were less likely to be vaccinated. Differences are likely due to the interplay between systemic barriers to access, and cultural/ social influences impacting uptake.