Risk modelling the mortality impact of antimicrobial resistance in secondary pneumococcal pneumonia infections during the 2009 influenza pandemic.

OBJECTIVES

The aim of this study was to estimate the impact of antimicrobial resistance (AMR) in secondary pneumococcal pneumonia infections on global mortality during the 2009 influenza pandemic, to estimate future pandemic mortality risk and to inform pandemic preparedness.

METHODS

Risk analysis modelling was conducted using a multivariate risk formula. Literature reviews were conducted to generate global central estimates for each of the parameters of the risk formula in relation to the 2009 influenza pandemic, secondary pneumococcal pneumonia, rates of AMR, and pneumococcal vaccine efficacy as a component of pandemic preparedness.

RESULTS

Global Streptococcus pneumoniae AMR was estimated at 21.8% to 27.6%, and contributed to 1.8% to 2.3% of deaths during the 2009 influenza pandemic. When directly applied to mortality due to multidrug resistance, pneumococcal vaccination could potentially prevent 1277 to 3754 deaths and could have reduced mortality from multidrug-resistant S. pneumoniae to 1% to 1.2%.

CONCLUSIONS

AMR in secondary pneumococcal infections contributed towards a small percentage of the global mortality during the 2009 influenza pandemic. Increased S. pneumoniae AMR could result in a three- to four-fold rise in mortality due to secondary pneumococcal infections in future influenza pandemics. Pneumococcal vaccination has an important role in preventing pneumococcal co-infections and combating AMR in all populations, and should be considered a key component of influenza pandemic preparedness or early action plans.