At least 10 people in the Northwest Territories have reported allergic reactions to the H1N1 flu vaccine, but none have been life-threatening to date, health officials confirm.

When the N.W.T. launched its mass immunization campaign last week, ambulances were seen taking people to hospital from a Yellowknife vaccine clinic with reactions to the swine flu shot.

Territorial health officials told CBC News Wednesday that there have been 10 to 15 true adverse reactions to the vaccine to date. That works out to about one in every 1,000 people who have received the shot.

None of those reactions so far have involved severe anaphylaxis, or the swelling of the throat, said Dr. Kami Kandola, the N.W.T.'s chief public health officer.

"We've seen people with hives, we've seen people with itchy throats, but we haven't had a true anaphylaxis," Kandola said.

About 18,000 people 45 per cent of the N.W.T.'s population were vaccinated for the H1N1 influenza virus in the first week of the territory's immunization campaign.

Normal reactions to the vaccine include a sore arm and mild flu-like symptoms for a short period of time after the shot is administered.

But Yellowknife resident John Carter said his arm was sore for days after he was vaccinated.

"Much greater swelling, much greater soreness, and it's lasted five days," Carter said, adding that he still does not regret getting the shot,

As with many flu vaccines, the H1N1 vaccine is cultured in egg, and that's what causes potentially life-threatening reactions such as anaphylaxis.

In other words, said Dr. Gerald Evans, an associate professor with Queens University's division of infectious diseases, such severe reactions are not associated with any of the other ingredients in the vaccine.

"It's a safe vaccine and serious adverse reactions are extraordinarily rare," Evans said.