Editors' ChoiceInfectious Disease

Two-pronged approach to prevent pneumonia

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Science Translational Medicine  15 Jul 2015:
Vol. 7, Issue 296, pp. 296ec121
DOI: 10.1126/scitranslmed.aac8563

Vaccines have resulted in some of the greatest biomedical and public health achievements in history. The eradication of smallpox, near eradication of polio, and profoundly reduced rates of diseases caused by infections, including some cancers, have all been accomplished through achievements made in vaccine science. A correlate to the numerous pathogens that are now targeted through vaccination is a multitude of doctor visits and needle sticks required to obtain recommended immunizations. To reduce the number of required vaccinations, manufacturers have developed multivalent vaccines, which can protect against more than one strain of a pathogen or even multiple different pathogens.

Despite the development of several multivalent vaccines, current medical recommendations in the United States still involve approximately 50 separate immunizations by the age of 18. Improving the potency and/or valency of existing vaccines is therefore of great interest to reduce pediatric immunizations. An interesting approach to this was recently described in a study of an experimental bivalent vaccine that protects against two major respiratory pathogens: influenza virus and the bacterium Streptococcus pneumoniae. This pathogenic duo is commonly to blame for cases of severe lung disease, with influenza causing the initial insult followed by pneumococcal pneumonia. The authors show that a conserved pneumococcal protein called PspA can be expressed on the surface of an influenza virus and that this virus, which does not replicate, can then be used to immunize against both pathogens. Potency of the immune response against PspA was significantly enhanced by delivery in the influenza particle, demonstrating an adjuvant effect achieved through use of the engineered influenza vector. The PspA antigen is highly conserved between pneumococcal strains and has potential as a vaccine antigen to improve strain coverage and elicit better immunity in infants over current pneumococcal vaccines. Although use of a bivalent influenza/pneumococcal vaccine for annual influenza vaccination seems unlikely, one could imagine using this vaccine to replace the existing pediatric doses of pneumococcal vaccine to reduce needle sticks; in addition, this vaccine could be used during an influenza pandemic to protect against the pandemic virus and boost immunity against pneumococcus, which contributes to death related to pandemic flu. Inventive approaches to vaccination such as the one described by Uraki and colleagues could lead to fewer lifetime immunizations and even improved immunity.

R. Uraki et al., A bivalent vaccine based on a PB2-knockout influenza virus protects mice from secondary pneumococcal pneumonia. J. Infect. Dis. 10.1093/infdis/jiv341 (2015). Abstract

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