Effectiveness of Vaccination in COVID-19

Effectiveness of Vaccination in COVID-19

To explore real-world effectiveness of coronavirus disease 2019 (COVID-19) vaccination on subsequent infection in patients with IBD with diverse exposure to immunosuppressive medications, a retrospective cohort study of patients in the VA with IBD diagnosed before December 18, 2020, the start date of the VHA patient vaccination program was carried out. 

IBD medication exposures included mesalamine, thiopurine, anti-tumor necrosis factor virologic agents, vedolizumab, ustekinumab, tofacitinib, methotrexate, and corticosteroid use. Inverse probability weighting and Cox’s regression were utilized with vaccination status as a time-updating exposure and computed vaccine effectiveness from incidence rates. 

A total of 14,697 patients, 7,321 of whom received at least 1 vaccine dose (45.2% Pfizer, 54.8% Moderna) were included. The cohort had median age 68 years, 92.2% were men, 80.4% were white and 61.8% had ulcerative colitis. In follow-up data through April 20, 2021, unvaccinated individuals had the highest raw proportion of SARS-CoV-2 infection (197 {1.34%} vs. 7 {0.11%}) fully vaccinated). Full vaccination status, but not partial vaccination status was associated with a 69% reduced hazard of infection relative to an unvaccinated status (HR 0.31), corresponding to an 80.4% effectiveness.

It was concluded that full vaccination (>7 days after the second dose), against SARSCoV-2 infection has an 80.4% effectiveness in a broad IBD cohort with diverse exposure to immunosuppressive medications. These results may increase patient and provider willingness to pursue vaccination in these settings. 

Khan, N., Mahmud, N. “Effectiveness of SARS-CoV-2 Vaccination in a Veterans Affairs Cohort of Patients with Inflammatory Bowel Disease with Diverse Exposure to Immunosuppressive Medications.” Gastroenterology 2021; Vol. 161, pp. 827-836.

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