H1N1 flu activity in Hamilton has already surpassed previous peak levels of seasonal flu and may still be on the rise, health officials say. Read full article here: H1N1 Rates Soars in Hamilton

The number of positive H1N1 tests spiked to 21 per cent last week, up from 6 per cent the prior week, said Dr. Chris Mackie, Hamilton's associate medical officer of health.

"We're seeing more cases now than we did at any time in the last two years," Mackie said. "(H1N1) spreads a lot more easily and that's in part because we don't have a baseline level of immunity in the community."

Flu activity in Hamilton is "normally at zero" at this time of year, he said. A typical flu season runs from Christmas to March, with the number of positive tests usually at about 20 per cent.

But the novel H1N1 virus has broken with patterns, causing an initial wave of infections in the spring that tapered off through the summer.

Dr. Arlene King, Ontario's chief medical officer of health, confirmed yesterday that a second wave of H1N1 has arrived in the province.