TOPLINE:

COVID booster vaccinations reduced the likelihood of hospitalization related to COVID in patients with autoimmune diseases, with monovalent and bivalent booster vaccines showing 38% and 32% effectiveness in reducing hospitalizations, respectively.

METHODOLOGY:

• Researchers conducted a real-world observational study to assess the effectiveness of an additional dose of a COVID vaccine in preventing hospitalization due to COVID and other outcomes.
• They used data from electronic health records of four US healthcare systems and included adults with systemic autoimmune rheumatic diseases (as well as psoriasis, inflammatory bowel disease, and multiple sclerosis) who received immune-modulating medication (including corticosteroid monotherapy). A non-immunocompromised comparison group that did not receive immune-modulating medication was also identified.
• Participants were divided into groups on the basis of the receipt of monovalent (n = 126,756; January to August 2022) or bivalent (n = 87,906; September 2022 to August 2023) COVID booster vaccines in addition to completion of the primary vaccination series; these groups were compared with people who only completed the primary vaccination series.
• The primary outcome was COVID-related hospitalization, defined as inpatient admission with an associated diagnosis of COVID and a positive SARS-CoV-2 test. Secondary outcomes included a diagnosis of COVID during any timepoint in the study and ICU admission during hospitalization.
• The effectiveness of booster vaccinations was calculated as 1 minus the summarized hazard ratio [HR], and the number needed to vaccinate was also determined.

TAKEAWAY:

• In patients with autoimmune diseases, the rate of COVID hospitalization was 15.6 vs 20.1 per 1000 person-years for those who received a monovalent booster vs for those who received only the primary series. For the bivalent booster, the rate was 7.9 vs 10.2 per 1000 person-years among recipients vs among non-recipients. In non-immunocompromised individuals who received monovalent or bivalent boosters, rates ranged from 1.6 to 3.6 per 1000 person-years.
• Monovalent and bivalent boosters showed an effectiveness of 38% and 32%, respectively, in reducing the rate of COVID hospitalization among patients with autoimmune diseases. The number needed to vaccinate to prevent one COVID hospitalization was 267 for the monovalent booster and 617 for the bivalent booster.
• The estimated vaccine effectiveness against diagnosed COVID was 10% for the monovalent booster and 5% for the bivalent booster.
• Vaccination with the monovalent booster vs the primary series alone reduced the risk for COVID-related hospitalization (summary HR, 0.63; 95% CI, 0.56-0.69); the bivalent booster vaccination also reduced the risk for hospitalization compared with no booster vaccination (summary HR, 0.68; 95% CI, 0.61-0.76).

IN PRACTICE:

“We conclude that the key benefit of monovalent and bivalent COVID-19 vaccination during the time periods studied was prevention of severe COVID-19, with greater effect in the cohort of persons with autoimmune disease than in non-immunocompromised persons,” the authors of the study wrote. “The current study provides further evidence for the value of increasing COVID-19 vaccine uptake in high-risk immunocompromised populations,” they added.

“As this current study by Ziemba et al. and others have shown, SARS-CoV-2 vaccines are beneficial for patients with SARD [systemic autoimmune rheumatic disease],” experts wrote in an accompanying editorial, further adding, “However, [effectiveness of additional vaccinations] decreases with increasing time following vaccination, and thus booster vaccines remain an important tool to maintain effectiveness over time, particularly among individuals with SARDs.”

SOURCE:

The study was led by Yonah C. Ziemba, MD, Department of Pathology and Laboratory Medicine, Northwell Health, New Hyde Park, New York, and Eric P. Elkin, MPH, Division of Research, Kaiser Permanente Northern California, Pleasanton, California. It was published online December 1, 2025, in The Journal of Rheumatology.

LIMITATIONS:

The reliance on administrative coding may have introduced inaccuracies in data collection. The rise of home antigen testing may have led to a lack of medical aid for mild SARS-CoV-2 infections, affecting infection estimates. Missing vaccine records could bias results toward a null outcome because undocumented vaccinations might place individuals in the comparison group.

DISCLOSURES:

The study was supported by the National Cancer Institute Serological Sciences Network, the Physician Researcher Program of The Permanente Medical Group Delivery Science and Applied Research Program, and the US Veterans Administration. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.