In older adults, an acute respiratory syncytial virus (RSV) infection was significantly associated with an increased risk of cardiovascular events, in particular ischemic stroke and heart failure (HF) hospitalization, according to a registry-based study published March 17 in JACC and presenting at ACC.25 in Chicago.

In a self-controlled case series, study authors Mats C. Højbjerg Lassen, MD, et al., used nationwide Danish health care registries to identify 2,655 adults over the age of 65 years who tested positive for RSV during the 2022-2023 winter season (mean age 78; 46% men). Of these patients, 18% had diabetes, 74% had hypertension, 11% had HF, 25% had atrial fibrillation and 23% had chronic obstructive pulmonary disease.

For the endpoints of HF hospitalization, ischemic stroke and myocardial infarction (MI), researchers compared the incidence within the risk interval of 14 days after a positive RSV test result and within the control interval of Sept. 16, 2022, to May 31, 2023. Each patient served as their own control.

Results showed a 4.4-fold increase in HF hospitalization, with 13 events during the risk interval and 61 events during the overall observation period and an 8.1-fold increase in ischemic stroke (7 and 21 events) (p<0.001 for both), as well as a 3.2-fold increase in MI (3 and 18 events; p=0.063). Results were consistent after sensitivity analyses.

Additionally, researchers found a 5-fold increase in major adverse cardiovascular events (23 and 97 events in the at-risk and control intervals) and a 6.3-fold increase in any cardiovascular event (56 and 199 events (p<0.001 for both). Of all cardiovascular events, 67.9% occurred during the same hospitalization as the RSV diagnosis.

"These results suggest that RSV infection may confer an increased risk of cardiovascular events, raising important clinical considerations regarding the management of older adults during RSV outbreaks," write the authors.

In an accompanying editorial comment, Pekka J. Vartiainen, MD, PhD; Yuan Huang, PhD; and Mitsuaki Sawano, MD, call RSV "more than an infant's respiratory illness," noting that in the U.S., "RSV is estimated to cause up to 160,000 hospitalizations and 10,000 deaths annually in adults over 65." With RSV vaccines demonstrating an 80% real-world effectiveness in preventing severe RSV infections, they note that a key question is who to prioritize for vaccination, beyond the current focus on preventing acute infection.

"Understanding the full score of RSV's impact could be crucial in preventing yet another global health crisis," write Vartiainen, Huang and Sawano. While they laud the study for presenting a longitudinal view on older adults with rigorous control for confounders, they note the study's self-controlled design leads to limitations, and further research is required.