WHEELING -- A bad batch of the H1N1 flu vaccine is giving some people a severe allergic reaction but it appears to be confined to Canada, according to the World Health Organization.

Canada has stopped using a batch of the H1N1 vaccine after six people came down with severe allergies.

The Public Health Agency of Canada asked nearly half of the country to stop using the 172,000 doses of the vaccine in question. The WHO is waiting for test results. At least 65 million doses of H1N1 vaccine made by various companies have been administered so far worldwide.

H1N1, a mixture of swine, bird and human viruses, has killed at least 6,770 people globally, according to the WHO. Most people suffer mild symptoms such as aches or fever, but recover without special treatment, it says. As more and more Canadians are receiving the vaccine, there have been sporadic reports of problems.

Some Canadians are wondering how safe the shot is after a 19 month-old Novia Scotia boy died from an allergic reaction. An 80 year-old Quebec man also died after he got the shot. Health officials say it's too soon to link the two.