Several factors influenced the likelihood of COVID-19 vaccination among patients with cancer who already had COVID-19, according to a study published in Cancer.
Researchers evaluated vaccination rates in 2021 among patients with cancer who had a SARS-CoV-2 infection in 2020. Cancer type, comorbidities, age, social determinants of health (SDOH), and timing of COVID-19 diagnosis were all associated with vaccination.
This study included data from 1155 cancer patients enrolled in the American Society of Clinical Oncology’s COVID-19 registry (ClinicalTrials.gov Identifier: NCT04659135). All patients were infected with SARS-CoV-2 during 2020 — 141 in the first half of the year and 1014 from July to December.
The patients’ median age at COVID-19 diagnosis was 64 years, 59.1% were women, and 71% were non-Hispanic White. Patients had nonmetastatic solid tumors (40%), metastatic solid tumors (34%), B-cell hematologic malignancies (20%), and non-B-cell hematologic malignancies (6%).
The primary endpoint was time to first vaccination after January 1, 2021. (The first emergency use authorization for a COVID-19 vaccine was granted in December 2020 for Pfizer-BioNTech’s monovalent vaccine.)
There were 690 patients who had at least 1 vaccine dose and 662 who were considered fully vaccinated. Among the fully vaccinated, 637 had received 2 doses of an mRNA vaccine, and 25 had received 1 dose of the Janssen vaccine.
From January 1, 2021, the median time to vaccination was 99 days. An estimated 59% of the cohort had been vaccinated by June 1, 2021, and 67% had been vaccinated by August 1, 2021. By March 1, 2022, the overall cumulative vaccination rate was an estimated 85%.
Age, cancer type, comorbidities, the timing of COVID‐19 diagnosis, and area-level SDOH were all associated with vaccination in a multivariable model. Patients with any comorbidity had a lower likelihood of vaccination than patients with no comorbidities (hazard ratio [HR], 0.83; 95% CI, 0.73-0.95).
In addition, there was a lower likelihood of vaccination among patients with metastatic solid tumors (HR, 0.85; 95% CI, 0.73-0.98) or non-B‐cell hematologic malignancies (HR, 0.71; 95% CI, 0.54-0.93), compared with patients who had nonmetastatic solid tumors.
Patients who were diagnosed with COVID‐19 earlier in 2020 were more likely to be vaccinated. Compared with patients diagnosed in November to December, patients diagnosed in February to June had an HR of 1.40 (95% CI, 1.14-1.73), and patients diagnosed in July to October had an HR of 1.27 (95% CI, 1.10-1.46).
When the researchers looked at area‐level SDOH variables, they found a lower likelihood of vaccination in areas with lower education attainment (fourth vs first quartile: HR, 0.70; 95% CI, 0.54-0.90) and higher unemployment rates (second and fourth quartiles vs first quartile: HR, 0.79; 95% CI, 0.63-0.99).
The researchers assessed the link between age and vaccination during 2 time periods — from January to March 2021 and from April 2021 to April 2022. There were no significant associations between age and vaccination in the second time period.
In the first time period, however, older patients were more likely to get vaccinated. When compared with patients younger than 50 years, the HR was 2.76 (95% CI, 2.01-3.83) for patients aged 80 years and older, 1.99 (95% CI, 1.60-2.49) for patients aged 65-79 years, and 1.35 (95% CI, 1.09-1.66) for patients aged 50-64 years.
“[T]hese findings, including the identification of subgroups of patients with cancer who remain unvaccinated, should be used to inform strategies to communicate information about vaccine safety and efficacy and vaccine recommendations to patients with cancer,” the researchers concluded.
Disclosures: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Kurbegov D, Bruinooge SS, Lei XJ, et al. Rate of COVID‐19 vaccination among patients with cancer who tested positive for severe acute respiratory syndrome‐coronavirus 2: Analysis of the American Society of Clinical Oncology Registry. Cancer. Published online March 15, 2023. doi:10.1002/cncr.34726