Department of Research & Evaluation News

A new study by Kaiser Permanente has shown that the ABRYSVO respiratory syncytial virus vaccine is very effective in reducing emergency room visits and hospital stays due to RSV among older adults.

“This Kaiser Permanente research demonstrated the real-world effectiveness of RSV vaccination among those 60 and over,” said lead author Sara Y. Tartof, PhD, MPH, from the Kaiser Permanente Southern California Department of Research & Evaluation.

The study, published in December 2024 in JAMA Network Open, examined more than 7,000 Kaiser Permanente Southern California patients who were 60 years and older and either hospitalized with lower respiratory tract disease or tested for RSV in an emergency room between November 2023 and April 2024. Dr. Tartof also shared these findings at the IDWeek Conference in Los Angeles in September 2024.

The FDA approved ABRYSVO, Pfizer’s recombinant RSVPreF vaccine, in June 2023 for people 60 and older. (GSK’s recombinant RSVPreF3 adjuvanted vaccine, Arexvy, was also approved for the same age group.) Approval of the Pfizer vaccine was based on results of the RENOIR clinical trial, which showed that the vaccine prevented RSV ­associated acute lower respiratory tract illness in older adults.

The Kaiser Permanente study found that the ABRYSVO vaccine was 91% effective at preventing RSV-related emergency visits and hospital admissions among people age 60 and over. Unlike clinical trials such as RENOIR, this study included patients with compromising health conditions, representing a sicker but more typical patient population.

Based on the study, vaccinating about 250 people could prevent one RSV-related emergency or hospital visit in the first season after vaccination. The vaccine greatly reduced severe RSV cases among older adults, including those with chronic health issues or compromised immune systems.

According to study authors, these findings support the use of the ABRYSVO^® vaccine in older adults and provide an opportunity to reduce severe disease, significantly given that according to the CDC, just 1 in 4 adults in this age range have received the vaccine.

Alongside Dr. Tartof, other study authors include Gabriella Goodwin, MS, Jeff Slezak, MS, Vennis Hong, MPH, Bradley Ackerson, MD, Sally Shaw, DrPH, MPH, Julie A. Stern, MPH, Banshri Kapadia, MS, Brigitte C Spence, MPH, and Brandon Chia, of the Department of Research & Evaluation; Negar Aliabadi, MD, MS, Qing Liu, MS, Gonzalez, MS, Robin Hubler, MS, Luis Jodar, PhD,  Bradford D. Gessner, MD, Elizabeth Begier, MD, MPH, of Pfizer, Inc; and Joseph A. Lewnard, PhD, of the University of California, Berkeley. Dr. Tartof is also affiliated with Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena