TORONTO -- Medical experts are still debating whether to offer a separate swine flu vaccine for Ontarians, Chief Medical Officer of Health Dr. David Williams says.

The annual flu vaccine offered free to provincial residents is already in production for this fall's influenza season, he said. "So if we're going to make one for H1N1 it would have to be a separate one," Williams said yesterday.

Ontario health officials say a vaccine can be produced in time for this fall.

The number of confirmed cases of the human swine flu in Ontario hit 284 yesterday, an increase of 97 over the past two days.

Symptoms for the vast majority of its victims have been mild, although two people with "underlying" medical conditions have needed treatment in hospital. The GTA has the most confirmed cases of H1N1, although there are a smattering around Ontario.

Ontario labs have performed 6,000 tests and are now finding HIN1 cases where patients just felt slightly unwell. "We had a couple who didn't know they had anything," Williams said.

The same scale of testing will not continue over the summer in Ontario -- influenza traditionally wanes after April -- but "sentinel" physicians across the province will be on guard for any signs that H1N1 is coming back.

The World Health Organization will monitor the strain.

ANTONELLA.ARTUSO@SUNMEDIA.CA