In a retrospective analysis, the respiratory syncytial virus (RSV) vaccine (Abrysvo) was associated with fewer hospitalizations and emergency department (ED) visits among older patients during the first season of vaccine rollout.
From November 2023 to April 2024, during the first five months of vaccine availability, RSV vaccine efficacy was 90% (95%) in adults 60 years and older, after adjusting for hospitalization or emergency department visits. CI 24-99), reported Sarah Tartoff, Ph.D., MPH. Kaiser Permanente, Pasadena, California, speaking at the IDWeek Annual Meeting in Los Angeles.
Additionally, secondary analyzes showed adjusted vaccine efficacy of 93% (95% CI 47-99) for RSV-associated acute respiratory illness (ARI) ED visits and 91% adjusted vaccine efficacy for RSV-associated ARI ED visits or hospitalizations. (95% CI 61). -89).
Of the positive test cases, 99.7% (n=371) were unvaccinated and 0.3% (n=1) were vaccinated. Of the tested negative controls, 96.8% (n=480) were unvaccinated and 3.2% (n=16) were vaccinated.
The FDA approved Pfizer’s recombinant RSVPreF vaccine for use in people 60 years of age and older in June 2023, shortly after approving GSK’s recombinant RSVPreF3 adjuvanted vaccine (Arexvy) for the same age group. The approval of the Pfizer vaccine is based on results from the RENOIR trial, which showed it prevents RSV-related acute lower respiratory tract illness in older adults.
However, the RENOIR trial had a limited number of visits for hospitalization and ED outcomes, “preventing the estimation of vaccine efficacy on more severe clinical outcomes,” Tartoff told attendees. Additionally, Renoir excluded people who are immunocompromised and those with the most severe comorbidities. He also noted that estimates of vaccine efficacy were not available for the oldest age groups.
Of note, more than 76% of the total patient population in the present study scored 3 or higher on the Charlson Comorbidity Index, indicating some degree of comorbidity burden. Additionally, more than 16% were immunocompromised.
A recent analysis of CDC data also demonstrated an association between RSV vaccination and lower hospitalization rates for people age 60 and older. This analysis also included high-risk older adults.
“The big question with these vaccines is whether immunity lasts in subsequent seasons, as there is no recommendation for boosters at this time,” said session moderator Tyson Bell, M.D., of the University of Virginia at Charlottesville. MBA commented.
“We are pleased to have evidence regarding immunocompromised patients. This is very remarkable,” he added.
Tartoff said her group plans to examine the durability of immunity from the Pfizer vaccine over successive respiratory phases in a follow-up analysis.
In June, the CDC’s Advisory Committee on Immunization Practices (ACIP) withdrew its original recommendation that all adults age 60 and older be eligible for RSV vaccination in the interest of shared decision-making. ACIP currently recommends one-time vaccination for all adults age 75 and older and adults 60 to 74 who are at high risk for severe RSV disease.
This observational, retrospective study using a test-negative design included older adults hospitalized or admitted to the emergency room with severe ARI and for whom RSV test results were available. By definition, severe ARI requires supplemental oxygen.
Tartof et al. conducted their analysis using electronic medical record data from Kaiser Permanente Southern California. The study population of 5,120 patients was divided into RSV-positive and RSV-negative cases, and each of those groups was then further divided into unvaccinated and RSV-vaccinated individuals using the Pfizer vaccine. It was done.
To test negative controls for the “strict” control definition used in the primary analysis, test negative for RSV, human metapneumovirus, and other vaccine-preventable pathogens, but not for vaccine-preventable pathogens. required a positive ARI event. Test negative controls for the “broad” control definition used in the sensitivity analysis included ARI events negative for RSV.
Approximately 61% of the total study population was 75 years of age or older. About 68% of cases testing positive were in this elderly group, compared with about 58% in the strict control group.
Only 2.7% of the total study population received the RSV vaccine. The majority (81%) of the study population were also hospitalized (compared to emergency department visits). This includes 74.5% of the RSV-positive case population.
One problem the researchers faced was the low uptake of RSV testing in the study population. To alleviate the problem of low laboratory testing rates for RSV, researchers tested recovered respiratory swabs collected for influenza/SARS-CoV-2 testing from acute care hospitals and inpatient contacts. did. Swabs were then tested for RSV using an 18-pathogen multiplex panel.
Katherine Kahn is a staff writer for MedPage Today, covering the infectious disease beat. She has been a medical writer for over 15 years.
disclosure
This study was funded by Pfizer. In other words, the co-author is a company employee.
Tartov disclosed institutional funding from Pfizer and GSK. The co-authors disclosed multiple relationships with industry.
Bell revealed his relationship with Shinogi.
primary source
ID week
Reference source: Tartof S et al. Real-world Abrysvo vaccine efficacy (VE) against respiratory syncytial virus (RSV0-associated severe acute respiratory infection (ARI) hospitalizations and emergency department (ED) visits — Kaiser Permanente of Southern California (KPSC)” ), November 2023 – April 2024” IDWeek 2024.
