More than 100,000 doses of the H1N1 vaccine are being withdrawn across the country, after Manitoba health officials announced Thursday they'd noticed a higher-than-usual number of allergic reactions from one batch.

Vaccine manufacturer GlaxoSmithKline has asked several provinces to set aside the 170,000 doses from the questionable batch.

GSK say the batch recall is a precaution an they will investigate to see whether there is something wrong with the batch.

"GSK is taking this cautionary action because the Public Health Agency of Canada has received a higher than expected number of reports of anaphylaxis in this lot number compared to other lots," the company said in a written statement Thursday.

One or two allergic reactions are expected in a batch that size. But health officials recorded six severe allergic reactions and alerted GSK.

Dr. Joel Kettner, Manitoba's Chief Medical Officer of Health, urged people not to be alarmed, noting the anaphylaxis reactions were short-lived and all the patients recovered.

"We've been asked by the manufacturer GlaxoSmithKline not to use this vaccine at this time, pending further investigation," said Kettner at a press conference Thursday.

"We are being cautious and following the advice... to hold onto the remaining stock until we get further information."

About 1,500 doses of the vaccine were sent to Ontario, but officials say none were administered. Officials are now shelving them until the investigation is complete.

The Alberta government has stopped giving out doses from the same batch, although it says it has not seen a jump in allergic reactions.

Health officials say the batch being investigated is fairly small, so it should not have an impact on the overall supply.

Earlier this week, the country's chief public health officer, Dr. David Butler-Jones, noted that of the 6.6 million doses of H1N1 vaccine given so far to Canadians, there have been 36 serious adverse reactions reported.

Most involved allergic reactions that began within minutes of vaccination. All were treated promptly by medical people at the vaccination site.

Milder side effects, such as nausea, soreness, headaches and fever, have also been seen, which is not unexpected. Seasonal flu vaccines have been known to cause such reactions every year.

One person is believed to have died from an anaphylactic reaction following vaccination, but Butler-Jones stressed the death hasn't been conclusively linked to the flu shot.

"It's important to remember that just because a medical event follows vaccination, it may not have been caused by the vaccination; it may have been caused by other factors, as unfortunate events continue to occur with or without vaccine," he told a news conference Tuesday.