SARANAC LAKE - New research from the Trudeau Institute shows that prior immunity to the flu plays a critical role in preventing secondary bacterial infections, a common problem that can lead to serious complications, including death.
The findings of Laura Haynes, Stephen Smiley and their colleagues at the nonprofit biomedical research center will be published in an upcoming issue of The Journal of Immunology, Trudeau officials announced in a Wednesday press release.
One of the reasons influenza infection can result in death is that it often sets the stage for secondary bacterial infections. These infections cause a number of diseases, like pneumonia, bronchitis and sinusitis. Bacterial pneumonia was the leading cause of death during both the 1918 and 2009 influenza pandemics, and pneumonia and influenza together are ranked as the eighth leading cause of death in the United States.
Stephen Smiley and Laura Haynes
(Photo courtesy of Trudeau Institute)
The current standard of care for bacterial pneumonia is the administration of antibiotics, which have limitations in their capacity to prevent or treat infection. That's why there is a need for improved preventive measures, especially continued widespread influenza vaccination.
Haynes and Smiley have used an animal model to examine how this susceptibility to secondary bacterial infections following influenza infection can be reduced to limit its occurrence. Their studies found that any prior immunity to influenza, whether from infection or vaccination, could significantly reduce susceptibility to subsequent bacterial infections. This prior immunity does not have to completely prevent influenza infection; it just needs to reduce the inflammatory immune response to the virus in the lungs. In other words, you may still become ill with influenza, but you have a much greater chance of not dying from a secondary bacterial infection.
Among the study's important findings: prior immunity can be generated by vaccinations that do not match the infecting influenza virus. This point is especially important in the case of newly emerging influenza strains that can spread rapidly and for which there are no existing vaccines.
Haynes and Smiley also discovered that this protective immunity can be provided by vaccination with only a single, conserved, influenza protein or even by administration of antibodies to that protein, a strategy which would be beneficial for individuals that are considered high-risk and have reduced responses to traditional influenza vaccines, such as the elderly, the very young, the immunosuppressed (AIDS patients, those undergoing cancer therapy or organ transplantation), and others with underlying health problems.