The unadjuvanted version of the H1N1 vaccine is preferred for pregnant women because there hasn't been a lot of research on it during pregnancy. (Ron Heflin/Associated Press)

The federal government has increased its supply of H1N1 vaccine for pregnant women by 200,000 doses, Health Minister Leona Aglukkaq said Monday.

"Unadjuvanted vaccine is what we have recommended for pregnant women," Aglukkaq told a news conference in Ottawa, referring to the form of the vaccine that does not contain an additive, known as an adjuvant, that boosts the body's response to the vaccine.

Aglukkaq said she has heard concerns from pregnant women about having to wait for the vaccine without a booster.

"I am pleased to announce today that the government of Canada has secured an additional supply of 200,000 doses of non-adjuvanted vaccine from Australia," Aglukkaq said. "Very recently, I signed a special order to allow Canadians to access this vaccine."

Canada has already ordered 1.8 million doses of vaccine without the adjuvant from GlaxoSmithKline's facility in Quebec City. The 200,000 additional doses come from CSL Australia under a special order for emergency access.

The CSL option means Canadian pregnant women could start using the version without the adjuvant as early as next week, said Canada's chief public health officer, Dr. David-Butler-Jones.

GlaxoSmithKline's non-adjuvanted vaccine is expected to arrive in the first half of November.

"It's a very serious situation," Aglukkaq said. "We are seeing more cases in Canada. We are seeing more deaths in Canada."

Some Canadians receiving shots

Women who are beyond 20 weeks into their pregnancy or pregnant women with underlying health conditions should not wait until the non-adjuvanted doses of the swine flu vaccine become available, Aglukkaq said.

Rather, these women should get the advanced form of the vaccine that includes a booster to increase immune response, she said.

Last week, the Society of Obstetricians and Gynaecologists of Canada also said all evidence suggests that adjuvanted vaccines are just as safe as non-adjuvanted vaccines. But the preferred version for pregnant women is the non-adjuvanted version because there hasn't been a lot of research on the use of the adjuvant in pregnancy.

Europe is giving the same advice to pregnant women as Canada is, said CBC reporter Piya Chattopadhyay. Israel is telling pregnant women to wait for the non-adjuvanted version.

Ottawa approved the booster version of the vaccine for all other Canadians over the age of six months last Wednesday.

The availability of the adjuvanted vaccine differs from region to region, but in most cases people can get the shot this week — some as early as Monday. New Brunswick and Quebec have already started their mass immunization programs. In Ontario, health-care workers are first up for the H1N1 vaccine.

It's not yet clear what Canada will do with any excess doses. Discussions are underway with the World Health Organization to have the Canadian doses approved for worldwide use, federal health officials said.

Canada ordered adjuvanted vaccine in part to stretch supplies, since global reserves of the H1N1 vaccine are limited. When the adjuvant is added, a dose of the vaccine can protect four people instead of one, Butler-Jones has said.

It is also thought that the adjuvant may help produce an immune response against similar versions of the virus, if the H1N1 pandemic virus mutates or changes. So far, scientists say the H1N1 virus has remained the same.