New research indicates that community-acquired pneumonia should not be regarded as a seasonal disease, as it occurs throughout all seasons; however, the pathogens that cause the condition are clearly subject to seasonal variations.

In the observational study carried out in the Hospital Clinic of Barcelona, Spain, community-acquired pneumonia occurred more frequently in the winter than in other individual seasons, but two-thirds of cases occurred in spring, autumn, and summer combined.

"To our knowledge, this is the most comprehensive analysis of seasonal variations of aetiology, based on prospectively collected data over 12 years of a large population with community-acquired pneumonia," wrote the authors of the Respirology study.

Article: Seasonality of pathogens causing community-acquired pneumonia, Catia Cilloniz, Santiago Ewig, Albert Gabarrus, Miquel Ferrer, Jorge Puig de la Bella Casa, Josep Mensa and Antoni Torres, Respirology, doi: 10.1111/resp.12978, published 17 January 2017.