Six bad reactions to swine flu vaccine in Canada: official (Update)

All of the cases of anaphylactic shock were linked to a single batch or 172,000 doses of Aprepanrix vaccines made by GlaxoSmithKline (GSK) distributed starting November 2, said Caroline Grondin, a spokeswoman for Canada's health ministry.

Distribution of the batch to six provinces -- British Columbia, Alberta, Saskatchewan, Manitoba, Ontario and Prince Edward Island -- was halted, she said.

But she could not say how many doses had been used before distribution was suspended.

The health ministry believes the number of adverse reactions is abnormally high and has asked officials to investigate. One allergic reaction in 100,000 doses is the currently accepted norm.

Anaphylactic shock is a severe, rapid and sometimes fatal allergic reaction to a foreign substance such as a vaccine, shellfish or insect venom. Symptoms include difficulty breathing and a sudden drop in blood pressure.

It is a serious medical issue, said Grondin, but anyone who received the vaccines and did not have a reaction should not worry.

The A(H1N1) vaccine is safe and effective, she insisted. "The fact that we've uncovered problem with a specific batch shows that our monitoring system works," Grondin told AFP.

The World Health Organization (WHO), which first alerted health authorities of potential problems with this batch of vaccines, has not changed its recommendations regarding swine flu vaccines.

These remain, according to the WHO, the most effective way to fight the virus, which has killed some 6,750 people worldwide since it first appeared in March.

(c) 2009 AFP