Risk factors for COVID-19 hospitalization after COVID-19 vaccination: a population-based cohort study in Canada. (February 2023)

• Record Type: Journal Article
• Authors: Velásquez García, Héctor A.; Adu, Prince A.; Harrigan, Sean; Wilton, James; Rasali, Drona; Binka, Mawuena; Sbihi, Hind; Smolina, Kate; Janjua, Naveed Z.
• Is Part Of: International journal of infectious diseases. Volume 127(2023)
• Page Start: 116
• Page End: 123
• Publication Date: 2023-02
• Subjects: COVID-19 -- Vaccination -- Hospitalization -- Risk factors -- Canada; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2022.12.001
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: The risk factors for COVID-19-related hospitalization differ by vaccination status. The overall risk is more reduced among vaccinated individuals. Seniors and those with underlying medical conditions may benefit from booster doses. Abstract: Objectives: With the uptake of COVID-19 vaccines, there is a need for population-based studies to assess risk factors for COVID-19-related hospitalization after vaccination and how they differ from unvaccinated individuals. Methods: We used data from the British Columbia COVID-19 Cohort, a population-based cohort that includes all individuals (aged ≥18 years) who tested positive for SARS-CoV-2 by real-time reverse transcription-polymerase chain reaction from January 1, 2021 (after the start of vaccination program) to December 31, 2021. We used multivariable logistic regression models to assess COVID-19-related hospitalization risk by vaccination status and age group among confirmed COVID-19 cases. Results: Of the 162, 509 COVID-19 cases included in the analysis, 8, 546 (5.3%) required hospitalization. Among vaccinated individuals, an increased odds of hospitalization with increasing age was observed for older age groups, namely those aged 50-59 years (odds ratio [OR] = 2.95, 95% confidence interval [CI]: 2.01-4.33), 60-69 years (OR = 4.82, 95% CI: 3.29, 7.07), 70-79 years (OR = 11.92, 95% CI: 8.02, 17.71), and ≥80 years (OR = 24.25, 95% CI: 16.02, 36.71). However, among unvaccinated individuals, there was a graded increase in odds of hospitalization with increasing age, starting at age group 30-39 years (OR = 2.14, 95% CI: 1.90, 2.41) to ≥80 years (OR = 41.95, 95% CI: 35.43, 49.67). Also, comparing all the age groups to the youngest, the observed magnitude of association was much higher among unvaccinated individuals than vaccinated ones. Conclusion: Alongside a number of comorbidities, our findings showed a strong association between age and COVID-19-related hospitalization, regardless of vaccination status. However, age-related hospitalization risk was reduced two-fold by vaccination, highlighting the need for vaccination in reducing the risk of severe disease and subsequent COVID-19-related hospitalization across all population groups.