-The Seasonal Influenza vaccine may help protect against an infection with the Swine flu H1N1.  This is according to a study published in the latest issue of the British Medical Journal.

The Flu vaccine contains a unique set of proteins that stimulate the immune system to respond to three of the most common influenza viruses circulating during the current season.

Although the Seasonal Flu vaccine is different than the Swine Flu vaccine, this year the Seasonal Flu vaccine contains an “H1N1 Flu”-like protein.  The study investigators sought to clarify whether the Seasonal Flu vaccine offered any protection against the Swine Flu H1N1 virus.

The study investigators retrospectively analyzed 240 patients, of which 60 patients had confirmed Swine Flu (H1N1) infection and 180 control patients.

Study investigators report that patients who developed Swine Flu were significantly less likely to have received the Seasonal Flu vaccine.  The Seasonal Flu vaccine appeared to have an effectiveness of 73% against the Swine Flu H1N1.  Additionally, study authors report that none of the patients who were vaccinated with the Seasonal Flu vaccine died from Swine Flu.

Study authors caution, however, that the Seasonal Flu vaccine should in no way replace vaccination against the Swine Flu.

This is an important study in that it shows a possible partial protection against Swine flu from the regular Seasonal Flu vaccine.
Other studies conducted by the CDC have also shown that the flu vaccine may protect against an influenza virus strain that was not included in that vaccine.
While these findings are interesting, people should continue to follow the CDC guidelines for the Swine Flu H1N1 vaccination.
Cristopher Geiler MD
BMJ. Published October 6, 2009