Why RSV matters more with asthma or COPD

What the review examined

The researchers gathered evidence from 40 studies published between 2000 and late November 2023. Each study had to include adults aged 18 or older and information about confirmed respiratory syncytial virus (RSV) infection together with asthma or COPD. The team pulled out details on how often asthma or COPD appeared in RSV-infected adults, RSV-related hospital admissions, complications, and deaths.

What the studies compared

For each outcome, the researchers compared people who had asthma or COPD with people who did not have that particular condition, or they described what happened among RSV-infected people who had the condition. Because these were observational studies gathered from medical records and surveillance programs, the review can describe patterns, but it cannot prove that the lung condition alone caused the poorer outcomes.

How common were hospital admissions?

In hospital-based studies, asthma and COPD were common among adults with RSV infection. Pooled estimates suggested about 19% of RSV-infected adults in these settings had asthma and about 31% had COPD. People with asthma were consistently more likely to have an RSV-related hospital admission than people without asthma; in studies without statistical adjustment, the rate was about 2 to 3.6 times higher, and in an analysis that adjusted for age and ethnicity the rate was about 6.7 to 8.2 times higher. For COPD, the gap was larger still: crude comparisons ranged from about 3.2 to 13.4 times higher, and adjusted comparisons from one study were about 9.6 to 9.7 times higher.

Serious flare-ups and deaths

The most frequently reported complications were flare-ups of the underlying lung disease. In one study of hospitalized adults aged 60 or older with asthma and RSV, 64.9% had an asthma flare-up. For COPD, reported flare-up rates ranged from about 57% to over 80%, but the highest figure came from a study that included both hospital and outpatient care, so it does not describe only hospitalized patients. Some hospitalized patients needed intensive care or mechanical ventilation, including 21% of adults with COPD and RSV infection in one Hong Kong hospital study. Deaths were reported in a minority of cases, but percentages varied widely: 2.6% to 4.3% for asthma and 2.8% to 17.8% for COPD. Those death figures are not directly comparable because some studies counted deaths only during the hospital stay, while others also included deaths within 30 days after discharge.

How to read these findings

These studies used different settings and definitions: some included only hospitalized people, others mixed hospital and outpatient care, and follow-up periods for death varied. The hospitalization comparisons are rates across groups, not the chance that a given infected person will be admitted. Even with those differences, the direction was consistent - people with asthma or COPD had more RSV-related hospital admissions. The review authors concluded that these data can inform policy decisions around RSV vaccines and improve preventive care in this high-risk population.