Adults are more likely to experience severe infections from respiratory syncytial virus (RSV) if they have certain high-risk conditions (HRCs), particularly asthma, congenital immunodeficiency, chronic kidney disease, or an organ transplant, or are taking immunosuppressive medications.

Specifically, people with an HRC were 62% more likely to get lower respiratory tract disease, according to a study recently published in Open Forum Infectious Diseases.

Lower respiratory tract disease occurs in the lungs and below the voicebox, which usually manifests as pneumonia or bronchitis. Mayo Clinic researchers found that the rate of this type of RSV-associated illness increased to a 117% higher risk among HRC adults who are under 50. 

The study also examined the risk of acute respiratory illness from RSV, a milder upper respiratory infection. They found no statistically significant difference between those with an HRC and those without. 

Younger adults overlooked in RSV surveillance

The study was conducted from October 2022 to September 2024. The researchers had 7,504 Mayo Clinic primary care patients collect their own nasal and throat swab specimens at home at the onset of symptoms. Volunteers were based in Minnesota, Wisconsin, Florida, and Arizona. All were 18 to 64 years old, and 45% had an HRC.

The authors note this study is the largest US prospective, community-based RSV surveillance study to include people younger than 60 years with HRCs published since 2005. 

“As younger adults with HRCs are often underrepresented in RSV surveillance, these results can support the value of considering prevention strategies in this age group,” they say. 

They added that it may be justified to expand the Centers for Disease Control and Prevention recommendation of the RSV vaccine to adults under 50.