Rhedin S, Lundholm C, Osvald EC, et al. - The authors conducted a nationwide register-based cohort study of > 900,000 Swedish children to evaluate the relationship between pneumonia in infancy and prevalent asthma at 4 years and to ascertain if the association has changed after the introduction of nationwide pneumococcal conjugate vaccine (PCV) immunization as this has led to a shift in pneumonia etiology. Findings suggested that the risk of asthma after a pneumonia diagnosis in infancy was slightly higher for those born during the PCV period compared with those born before the PCV period when the proportion of viral pneumonia etiology was also higher. Children diagnosed with pneumonia in infancy have a significantly increased risk of developing prevalent asthma at the age of 4, which may have implications for future asthma preventive measures and should be considered when assessing the morbidity that can be attributed to pneumonia.