Study raises red flag for universal flu vaccine; may explain 2009 ‘Canadian problem’

TORONTO – A new study raises a red flag for work being done to try to come up with a vaccine that would protect against all subtypes of influenza.

The study describes a phenomenon where vaccination against one strain of flu actually seems to raise the risk of severe infection following exposure to a related but different strain of influenza.

While this work was done in pigs, it is reminiscent of something that was observed in people in Canada during the 2009 H1N1 pandemic.

Several research groups across the country reported seeing higher rates of pandemic H1N1 infection in people who had been vaccinated against seasonal flu in the fall of 2008.

Initially the effect was only reported from Canada and became known as “the Canadian problem” in influenza research circles.

The authors of this new study call it phenomenon vaccine-associated enhanced respiratory disease and they are reporting on research that shows the effect in piglets.

The study is published today by the journal Science Translational Medicine. The authors work for the U.S. Food and Drug Administration and the U.S. Department of Agriculture.

One of the senior authors, Dr. Amy Vincent of the USDA’s agriculture research service, says that more research is needed to see if the phenomenon happens in other species, including humans.

But she and her co-authors warn the findings should be considered by those developing and assessing experimental universal flu vaccines.