Studies Likely Underestimate RSV Incidence in Older Adults

A review of limitations from 71 studies that assessed the epidemiology of respiratory syncytial virus (RSV) suggests the incidence of RSV infection in older adults is likely underestimated, according to a paper published in the journal Infectious Diseases and Therapy.

“Underestimating the case burden of RSV in older adults will in turn underestimate the potential health benefits that can be gained from a vaccination program,” wrote corresponding author Elizabeth Begier, MD, MPH, of Pfizer Vaccines, Dublin, Ireland, and study coauthors. “The effectiveness and public health impact of vaccines will also be underestimated, as the recorded reduction in cases will be based on the incomplete proportion of cases captured prior to the vaccination program.”

The review investigated author-reported and other limitations in 71 studies reporting the incidence or prevalence of RSV infection in adults in high-income Western countries over the past 2 decades. 

Case definitions and sampling periods tailored to RSV were used in just a minority of studies, according to the review. Most relied on polymerase chain reaction (PCR) testing of upper respiratory tract samples alone instead of using dual-site sampling and/or the addition of serology to better identify RSV infections.

Studies also commonly limited their span to a single season despite seasonal variability and did not stratify results by age, thus failing to capture the burden of severe RSV disease in older adults. Many limited generalizability beyond a particular setting and did not include measures of uncertainty when reporting results, researchers reported.

“Well-designed studies and increased testing for RSV in patients with acute respiratory illness are required to capture the clinical and economic burden of RSV,” the authors wrote, “and adequately inform vaccine policy in older adults.”

Reference: 
Rozenbaum MH, Begier E, Kurosky SK, et al. Incidence of respiratory syncytial virus infection in older adults: limitations of current data. Infect Dis Ther. 2023;12(6):1487-1504. doi: 10.1007/s40121-023-00802-4