A possible link between respiratory syncytial virus (RSV) and pneumonia caused by Streptococcus pneumoniae may increase the risk of bacterial pneumonia in the presence of viral infection, especially for infants, a new study indicates.
Researchers analyzed data from State Inpatient Databases (Agency for Healthcare Research and Quality) on more than 700,000 hospitalizations of young children for RSV and more than 16,000 hospitalizations for pneumococcal pneumonia or septicemia between 1992 and 2009. They found that when RSV hospitalizations were high, the incidence of pneumococcal pneumonia also rose markedly: 20.3% of pneumococcal pneumonia cases in children aged younger than 1 year and 10.1% of cases in children aged between 1 and 2 years were linked to high RSV activity.
The study also found that once routine vaccination against S pneumoniae with the 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2000, hospitalizations for RSV among children aged younger than 1 year decreased markedly. (The PCV7 vaccine has since been replaced by PCV13 in the United States.)
The researchers didn’t have enough data to determine whether hospitalized children had both RSV and S pneumoniae, nor could they prove that children with one infection were more vulnerable to the other. Nevertheless, they note, their findings “provide evidence for an interaction between RSV and pneumococcal pneumonia.” Future research should examine whether to consider treatment for secondary bacterial infections in children with pneumonia who test positive for RSV, they say.