Ontario's chief medical officer of health expects the province will continue to vaccinate people against swine flu until the end of winter.

Dr. Arlene King told a Toronto news conference Friday that the H1N1 influenza virus is still circulating, and at any point throughout the season one can catch it.

King urged Ontarians who haven't yet been vaccinated to get the shot. She emphasized that the vaccine is safe and effective.

Since April, there have been 97 lab-confirmed deaths linked to H1N1 in Ontario.

A total of 1,541 Ontarians have been hospitalized because of the flu. The province currently has 223 confirmed cases in hospital, with 55 in intensive care. Thirty-nine of those 55 are on mechanical ventilation, King said.

To promote the vaccine to young Ontarians, the province is beginning an advertising campaign of posters and short ads in bars, restaurants and movie theatres geared toward college and university students. The hope is to increase vaccinations among people aged 17 to 24.

Ontario, with a population of 13.1 million, has received 5.9 million doses of the vaccine to date and expects 1.1 million more next week, King said. There is also the potential for the province to get another 1.1 million doses on top of that.