Witnesses to the swine flu's impact on patients' health has convinced some health care workers to get the vaccine.

Health care workers on the front lines are reporting that the H1N1 virus is hitting harder than predicted, and it's made them think twice about getting the shot, which is available first to the seriously ill and those in the medical field.

"We've seen a lot of people who had no medical issues, no heart (problems), no diabetes, end up in ICU and almost die," said ER nurse Patricia Faille.

"They were so sick, and this is not the same flu as we see every year. It's very different," she said, adding that she hadn't intended on getting the vaccine until she witnesses the swine flu's effects.

A mass vaccination began at 56 hospitals in Montreal Wednesday,

The seriously ill are prioritized, followed by medical staff and volunteers.

Staff at the Jewish General Hospital also said they intended to get the shot after hearing how virulent the illness can be.

"Now they're realizing that it's a good thing, vaccination. We're seeing many more cases right now so they're sensitive to it, and they're going ahead and getting vaccinated," said Isabelle Caron, the associate director of nursing at the Jewish General Hospital.

As health care workers deicde on whether or not to be vaccinated, government officials say the massive campaign to vaccinate more than one million Montrealers is going as planned, despite logistical challenges.

The vaccine is being delivered to 120 vaccination sites across the region.

Dr. Richard Lessard of Montreal's Public Health Department says the initial batch of 200,000 doses is ready to be delivered.

But he adds that they won't be rolled out all at once to prevent the units from being damaged by excessive handling.

The vaccine is sensitive to light and must be kept as cool and stable as possible.

Lessard assures Montrealers that there will not be any delays in administering the vaccine to those who need it.

Health official say at least 400 new cases of the flu have been reported in the last week, adding that the best prevention is vaccination.

The federal government recommends people who think they may have the virus to avoid public transit.