A Canadian study is making waves across the international press after reportedly finding evidence of an increased risk for swine flu infection among people who have taken the seasonal influenza vaccine. The research is preliminary and has not been peer-reviewed yet, but governments and the media are taking notice.
“There is emerging unpublished evidence that suggests an association between prior seasonal flu vaccination and getting the H1N1 flu,” explained Dr. Arlene King, Ontario’s Chief Medical Officer. “The nature of the association is unclear at this time, so we want people under 65 to wait to get the seasonal flu shot until after the H1N1 flu vaccine until we learn more about this.”
Across Canada, other public health officials were also debating delaying or eliminating their seasonal flu vaccination programs. At least five Canadian provinces have suspended their seasonal flu vaccine campaigns already, reportedly due to the new data.
According to an article by ABC News and other reports, the work suggested that people who had received a seasonal flu shot were about twice as likely to catch the swine flu compared with people who had not taken the shot. The research was prepared by “well known and capable” Canadian investigators, according to Reuters, Dr. Danuta Skowronski of the British Columbia Centre for Disease Control and Dr. Gaston De Serres of Laval University led the project. It involved around 2,000 people and was being peer-reviewed by an unnamed journal.
U.S. and global health officials were stumped. The World Health Organization announced that it would investigate the study while noting that, so far, this pattern was not being observed elsewhere. "The reason why this may be different in Canada and in this particular study than in other places of the world is not yet identified,” said the director of the WHO’s initiative for vaccine research. “It may be a study bias, it may be that something is real.” She said there were “intense” international discussions going on, according to the Canadian Free Press; "because now that it’s out, everybody feels that we must go to the bottom of it and see what’s real there."
A spokesman for the U.S. Centers for Disease Control and Prevention (CDC) stated that its scientists had not observed such a trend in America, adding: "It is difficult to speak about a study that has yet to be published." He continued by urging people to get both the seasonal and swine flu vaccines.
But even though the research has not been validated, some experts said it was important, the Canadian Broadcasting Corporation (CBC) reported. "This is obviously important data to help guide policy decisions,” explained Dr. Don Low, the chief microbiologist at Toronto’s Mount Sinai Hospital. He stressed that the study has not been validated yet, but noted that it was theoretically possible.
The CBC article, entitled "Seasonal flu shot may increase H1N1 risk," added: “Researchers know that, theoretically, when people are exposed to bacteria or a virus, it can stimulate the immune system to create antibodies that facilitate the entry of another strain of the virus or disease. Dengue fever is one example.”
It appears that not many people have seen the research. The authors are forbidden from discussing it while it is being peer-reviewed. But so far it has been taken seriously. Known internationally as the “Canadian problem,” these results will be important for people to follow.
How this story develops could play a key role in people’s decisions about the best course of action for the flu season ahead. But no matter what happens, in the United States — where local, state, and federal governments are considering legislation to mandate that citizens get the flu shot or be quarantined — all levels of government should allow Americans to decide for themselves whether to get a vacination or not.
Photo: AP Images
