Improving Understanding of Viral/Bacterial Coinfection in CAP: Public Health Watch

With community-acquired pneumonia (CAP), the numbers tell the story.

More than 5 million Americans are hospitalized with the infection annually. Some 50,000 die from the disease every year.

The vaccine has been estimated to be up to 70% effective at preventing it, yet less than 70% of Americans 65 years of age and older—the group most at risk for severe disease and death—receive it, according to the US Centers for Disease Control and Prevention.

We’ll let you decide how all of this contextualizes the current COVID-19 outbreak.

A group of researchers from the Hospital Universitari de Bellvitge in Barcelona has attempted to add to our understanding of CAP in non-ICU hospitalized adults with viral and bacterial coinfection (VBC), and it could certainly be argued that their findings also have implications for the management of all serious respiratory tract infections. Hint, hint.

Their results were published in Open Forum Infectious Diseases.

In all, the authors documented 1,123 episodes of CAP, including 57 (5.1%) cases of VBC-CAP,98 (8.7%) cases of viral CAP, and 968 (86.1%) cases of bacterial CAP. Notably, patients with VBC-CAP tended to be younger than those with bacterial CAP, with an average age of 54 years vs 71 years.

Perhaps not surprisingly, chronic respiratory disease was more frequent in patients with VBC-CAP (26.3% of cases) than in those with viral CAP (14.3% of cases). And, among 153 patients with influenza and CAP, those with VBC-CAP received empirical antiviral therapy with oseltamivir less often (56.1% vs 73.5%).

Finally, in general, the authors also found that patients with VBC-CAP had more respiratory distress (21.1% of cases) compared to those with viral CAP (19.4% of cases) and bacterial CAP (9.8% of cases) and, thus, required admission to the ICU more frequently (31.6% of cases) than those with bacterial CAP (12.8%). Admission to the ICU was also required in 31.6% of cases with viral CAP. Interestingly, the 30-day case-fatality rate was lower in those with VBC-CAP (3.5%) than it was in those with bacterial CAP (6.3%) but higher than in those with viral CAP (3.1%).

The authors also found that “lack of pre-hospital antibiotic administration, purulent sputum, and lack of empirical oseltamivir therapy were independent risk factors for VBC-CAP, when compared with the V-CAP and B-CAP groups.”

The authors did not respond to requests for comment. However, they wrote: “This study provides a real-world perspective of the relevance of VBC-CAP as a potential separate diagnostic category in adults admitted with CAP to conventional medical wards. Our work also emphasizes the urgent need to improve influenza vaccination coverage in patients with chronic underlying diseases. Randomized clinical trials are now required that use multiple PCR diagnostic tests as standard if we are to identify the true burden of coinfection in CAP. Such data can then be used to determine appropriate empirical and definitive treatment protocols.”