COVID-19 vaccines 87% effective at preventing hospitalization in immunosuppressed patients
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Three doses of either the BNT162b2 or mRNA-1273 vaccine are 87% effective at preventing hospitalization due to COVID-19 among patients taking immunosuppressive drugs, according to data published in The Lancet Rheumatology.
“Studies indicating reduced immune response to COVID-19 vaccination among individuals taking immunosuppressive medications have led to concerns regarding the effectiveness of vaccines within this group,” Malcolm Risk, MA, and Lili Zhao, PhD, both of the University of Michigan, in Ann Arbor, told Healio in a joint statement. “Estimating vaccine effectiveness within this group requires a large study population and accurate medication data, contributing to a scarcity of research on this topic. Given access to electronic health record (EHR) data from a large hospital system — Michigan Medicine — we felt we could address this gap in the literature."
“As far as we know, this is the first study reporting vaccine effectiveness against omicron in individuals taking immunosuppressive medications,” they added.
To further investigate the relationship between immunosuppressive therapies, mRNA vaccines and severe COVID-19 outcomes, Risk, Zhao and colleagues conducted a retrospective cohort study. They included vaccinated and unvaccinated patients who were aged 18 years or older and were part of the Michigan Medicine health system during the omicron-specific period of the pandemic from Dec. 16, 2021, through March 4, 2022.
The researchers included information from patients’ medical records at Michigan Medicine, including demographics, medications and SARS-CoV-2 test data, as well as immunization data from the Michigan State Registry. Patients were included in the analysis if they had a primary care physician in the Michigan Medicine health system and at least one visit to that physician in the past 18 months. Patients were excluded if they were aged younger than 18 years or received a vaccine other than the Pfizer-BioNTech or Moderna mRNA vaccines.
In their analysis, the researchers examined patients’ comorbidities, recent hospital visits and transplantation status. Patients receiving immunosuppressive therapies were identified as those receiving conventional or biologic disease-modifying antirheumatic drugs or glucocorticoids within 3 months of baseline. To be considered for this group, patients needed to have a prescription covering half of that time or more, or two prescriptions at least 30 days apart. The researchers identified SARS-CoV-2 infection using laboratory test results.
A total of 168,414 patients were included in the analysis, of whom 5,609 were receiving immunosuppressive therapies. In patients receiving those therapies, three doses of the Pfizer-BioNTech vaccine demonstrated an effectiveness of 50% (95% CI, 31-64) against infection, while three doses of the Moderna vaccine had an effectiveness of 60% (95% CI, 42-73) against infection. Meanwhile, three doses of both vaccines offered an effectiveness of 87% against hospitalization (95% CI, 73-93).
Patients receiving immunosuppressive DMARDs (HR = 2.32; 95% CI, 1.23-4.38) and those with bone marrow or organ transplant (HR = 3.52; 95% CI, 2.01-6.16) demonstrated an increased risk for hospitalization due to COVID-19, compared with those who had not received immunosuppressives or a transplant.
“Vaccination with a third dose of either mRNA-1273 (Moderna) or BNT162b2 (Pfizer) was effective at preventing SARS-CoV-2 infection in individuals taking immunosuppressive medications,” Zhao and Risk said. “Individuals taking immunosuppressive DMARDs, such as methotrexate, mycophenolate mofetil, or tacrolimus, or glucocorticoids — mainly prednisone — were at increased risk of SARS-CoV-2 infection and hospitalization due to COVID-19, compared with individuals taking no immunosuppressive medications."
“We did not have sufficient sample size to quantify waning immunity in individuals taking immunosuppressive medications, but we would expect vaccine effectiveness against SARS-CoV-2 infection to decline as time from most recent dose increases and with the rise of new subvariants of omicron,” they added. “Vaccine effectiveness against hospitalization due to COVID-19 appears more durable but we would also expect some degree of decline. Readers should note this when interpreting our results in the context of current pandemic conditions.”
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