Study: Pneumonia risk lower for COVID-19 than influenza, RSV

Editor's Note

Influenza and RSV infections more than double the risk of secondary Streptococcus pneumoniae infection, while COVID-19 is associated with a significantly reduced risk, according to a June 2 news brief from the Center for Infectious Disease Research and Policy (CIDRAP). The findings stem from a retrospective study of over 188,000 Veterans Affairs (VA) patients, published in Clinical Infectious Diseases.

As detailed in the article, researchers from the VA Western New York Healthcare System analyzed patient data from January 2015 through March 2025, focusing on individuals tested for S pneumoniae following confirmed viral infections. Among the 188,172 patients (mean age 70; 96% male), 8,165 tested positive for S pneumoniae.

CIDRAP reports that 10.0% of patients with influenza, 9.8% with RSV, and 2.3% with COVID-19 later developed S pneumoniae infection. In multivariable logistic regression analysis, influenza (odds ratio [OR] 2.39; 95% confidence interval [CI], 2.15–2.64) and RSV (OR 2.50; 95% CI, 2.07–2.99) were linked to significantly increased odds of pneumococcal infection. Prior COVID-19 infection, however, was associated with a 44% reduction in odds (OR 0.56; 95% CI, 0.50–0.62).

As detailed in the article, other factors associated with increased risk included current smoking (OR 1.09; 95% CI, 1.03–1.16) and chronic obstructive pulmonary disease (OR 1.36; 95% CI, 1.28–1.45). The study authors suggest that influenza and RSV may elevate risk by damaging lung tissue and creating more sites for bacterial colonization, while the mechanism behind COVID-19’s association with reduced risk remains unknown. “In the post-viral setting of influenza or RSV, empiric antimicrobial therapy with coverage for S. pneumoniae should be considered in patients presenting with clinical features suggestive of bacterial superinfection,” they wrote.