Study finds RSV vaccine highly effective in protecting older adults against severe disease, hospitalization and death

A multi-state study, published in The Lancet, is one of the first real world data analyses of the effectiveness of the RSV—short for respiratory syncytial virus—vaccine. VISION Network researchers report that across the board these vaccines were highly effective in older adults, even those with immunocompromising conditions, during the 2023–24 respiratory disease season, the first season after RSV vaccine approval in the U.S.

RSV vaccination provided approximately 80% protection against severe disease and hospitalization, Intensive Care Unit admission and death due to a respiratory infection, as well as similar protection against less severe disease in adults who visited an emergency department but did not require hospitalization, ages 60 and older. Of this population, those ages 75 and older were at highest risk of severe disease and were the most likely to be hospitalized.

The study was a collaboration between the Centers for Disease Control and Prevention (CDC) and geographically diverse U.S. health care systems and research centers with integrated medical, laboratory and vaccination records—all members of the CDC’s VISION Network.

“Unlike this data study, clinical trials for the RSV vaccine were underpowered to assess the effectiveness of the vaccines against severe disease requiring hospitalization. Addressing this gap in evidence, we were able to use the power of big data to determine RSV vaccine effectiveness, information needed to inform vaccine policy,” said study co-author Shaun Grannis, M.D., M.S.

“As a data scientist and a family practice physician, I encourage older adults to follow CDC guidance and get vaccinated for RSV as we enter this year’s and every year’s respiratory disease season.”

Dr. Grannis is vice president for data and analytics at Regenstrief Institute and a professor of family medicine at the Indiana University School of Medicine.

In the U.S., respiratory disease season typically commences in late September or early October and continues through March or early April.

RSV affects the nose, throat and lungs, causing substantial illness and death among older adults during these seasonal epidemics. In years prior to the availability of an RSV vaccine, an estimated 60,000 to 160,000 RSV-associated hospitalizations and 6,000 to 10,000 RSV-associated deaths occurred annually among U.S. adults aged 65 years and older, according to the CDC.

“No vaccine is 100% effective. An 80% vaccine effectiveness rate is quite impressive and higher than we see, for example, with the influenza vaccine,” said study co-author Brian Dixon, Ph.D., MPA.

“The bottom line is that using real world data from electronic medical records routinely captured in care for people from diverse walks of life, we found that having the vaccine was highly protective against hospitalization, severe illness and death.”

Dr. Dixon is interim director and a research scientist with the Clem McDonald Center for Biomedical Informatics at Regenstrief Institute and a professor at the Indiana University Indianapolis Fairbanks School of Public Health.

Dr. Dixon added, “Studies like this one are critical to understanding the effects of prevention techniques like vaccination. The annual cost of RSV hospitalization for adults in the U.S. is estimated to be between $1.2 and $5 billion. Preventing up to 80% of hospitalizations could result in major savings for consumers and the health system.”

VISION sites participating in the study were Permanente Northwest (Oregon and Washington), University of Colorado (Colorado), Intermountain Health care (Utah), Regenstrief Institute (Indiana), HealthPartners (Minnesota and Wisconsin), and Kaiser Permanente Northern California (California), representing 230 hospitals and 245 emergency departments.

Regenstrief contributes data and scientific expertise to the VISION Network.