Using a combination of sophisticated modelling and statistical analyses, David Fisman and colleagues show that infection with influenza likely increases the incidence of invasive pneumococcal disease (IPD). It is feasible that infection with influenza increases the short-term risk of bacterial invasion in individuals already colonized with Streptococcus pneumoniae (which causes IPD) by increasing the permeability of the lining of the airways to the bacteria. These findings suggest that some cases of IPD could be attributable to influenza, so the extension of influenza vaccination to school-age children and young adults (a group of people at particular risk of IPD who are not normally vaccinated against influenza) could reduce the incidence of IPD as well as the incidence of influenza.

Funding:
This project was supported by an operating grant from the Canadian Institutes for Health Research; (Wintertime Seasonality of Influenza and Invasive Bacterial Disease: Influence of Environment, Pathogen Interactions, Time Scales, and Geography) to DNF, a research fellowship of the Swiss National Science Foundation to SPK, and by a Career Scientist Award from the Ontario Ministry of Health and Long-Term Care and a Research Scholar Award from the University of Toronto Department of Family and Community Medicine to JCK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests:
DNF has received research funding from GlaxoSmithKline, Novartis, and Sanofi Pasteur, all of which manufacture vaccines against respiratory pathogens. AM has received research funding from GlaxoSmithKline and Sanofi Pasteur. The other authors declare that they have no competing interests.

Citation:
Kuster SP, Tuite AR, Kwong JC, McGeer A, the Toronto Invasive Bacterial Diseases Network, et al. (2011) Evaluation of Coseasonality of Influenza and Invasive Pneumococcal Disease: Results from Prospective Surveillance. PLoS Med 8(6): e1001042. doi:10.1371/journal.pmed.1001042

Click here to access the freely available paper.

Source:
Clare Weaver
Public Library of Science