A strange vaccine-related phenomenon spotted at the start of the 2009 flu pandemic may well have been real, a new study suggests.
Canadian researchers noticed in the early weeks of the pandemic that people who got a flu shot for the 2008-2009 winter seemed to be more likely to get infected with the pandemic virus than people who hadn’t received a flu shot.
Five studies done in several provinces showed the same puzzling and unsettling results. But initially research outside of Canada did not, and the effect was dismissed as “the Canadian problem.”
News of the unexpected findings broke at a time when countries in North America and parts of Europe were getting ready to start vaccinating their populations against the pandemic virus.
Some jurisdictions were also trying to figure out whether to offer the seasonal flu vaccine they had purchased — similar to the 2008-2009 shot — along with the pandemic vaccine, in case the seasonal flu viruses continued to circulate. Quebec opted not to offer the seasonal vaccine because of the concerns raised by the studies.
Many people in the flu research and public health communities found the whole event unhelpful, and many rejected the findings. Some suggested if there was a problem, it might have been with the flu vaccine used in Canada, because the problem wasn’t seen elsewhere.
But a new study suggests the findings may indeed have been real.Click through to the full report to learn more.