Katsurada N, et al. - The effect of virus infection on pneumonia mortality was elucidated among adults stratified by virus type and patient comorbidities in this multicentre prospective study. Viral infections were common in adult pneumonia, and their effect on pneumonia mortality varied by viruses and comorbidities.

Methods

• From September 2011 to August 2014, the researchers enrolled pneumonia patients aged ≥15 years.
• They tested sputum samples by in-house multiplex polymerase chain reaction assays to identify 13 respiratory viruses.
• They examined viral infection status and its effect on in-hospital mortality by age group and comorbidity status.

Results

• The researchers recruited 2,617 patients in the study and 77.8% were aged ≥65 years.
• They observed no comorbidities in 574 (21.9%) patients, chronic respiratory disease was noted in 790 (30.2%) patients, and other comorbidities in 1,253 (47.9%).
• They detected viruses in 605 (23.1%) patients.
• The most frequently identified virus was human rhinovirus (9.8%), followed by influenza A (3.9%) and respiratory syncytial virus (3.9%).
• They identified respiratory syncytial virus more frequently in patients with chronic respiratory disease (4.7%) than those with other comorbidities (4.2%) and without comorbidities (2.1%) (p=0.037).
• Between the 3 groups, the frequencies of other viruses were almost identical.
• Virus detection overall was not correlated with increased mortality (adjusted risk ratio (ARR) 0.76, 95% CI 0.53-1.09).
• However, in patients with chronic respiratory disease, influenza virus A and B were correlated with 3-fold higher mortality but not with other comorbidities (ARR 3.38, 95% CI 1.54-7.42).
• In patients with other comorbidities, paramyxoviruses were associated with markedly lower mortality (ARR 0.10, 95% CI 0.01-0.70, p=0.020), but this association was not observed with chronic respiratory disease.
• No influence was observed on these effects by age group.