Emergency rooms in Hamilton are over capacity, as local hospitals feel the strain of flu season spreading through the city.

Health officials across the country are reporting higher than normal lab-confirmed cases of the flu. Hamilton has mostly dodged that bullet, local officials say, with numbers sitting in the mid-level range for what the city usually experiences around this time of year.

But even without a larger-than-normal spike, hospitals are still over capacity, says Ian Preyra, chief of emergency medicine at St. Joseph's Hamilton. St. Joes is currently 28 beds over capacity due to the surge.

"When we're over capacity, it's not just a number. People really feel it," Preyra said. "It means those ambulances can't be offloaded, patients may wait longer, and patients who are admitted to hospital may wait to find a bed."

As is the norm when hospitals are crowded, code zero ambulance events — which is when there is only one or fewer ambulances across the service's entire fleet available for a call — have spiked. There have been 16 code zeros in Hamilton already this month, only halfway through January. 

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Code zero ambulance events have spiked in January during flu season, city statistics show. (CBC)

Last year there were 21 code zero events in all of January, and that was the highest number for a single month in the whole year. The union representing local paramedics has long said code zeros are dangerous. Union officials say they're caused by a surge in call volumes for help, coupled with increasingly long wait times offloading patients in local hospitals.

Hamilton Health Sciences is operating over capacity too, said spokesperson Lillian Badzioch in an email. "Our adult medical/surgical bed occupancy rate has been consistently over 105 per cent since October 2016 and was 114 per cent yesterday (Jan. 15)," she wrote.

Emergency department physicians have also identified that there has been an increase in overall respiratory complaints and that overall volume has gone up, she said.

Bad flu season catches hospitals off guard3:37

In the first week of January there were 44 lab-confirmed cases of flu in Hamilton, according to the city. There were 19 the week before, in the last week of 2017.

That's a middle-of-the-road situation for what Hamilton sees most years, said Dr. Ninh Tran, associate medical officer of health. Updated numbers of confirmed cases will be available on Thursday.

"That will give us a sense as to if the trend is going up," Tran said.

While Hamilton's numbers remain relatively steady, the number of people stricken by flu continues to rise across the country, with 15,572 laboratory-confirmed cases for the season as of Jan. 6, the Public Health Agency of Canada says.

The level of influenza activity is "in the higher range of expected levels for this time of year," the agency said in its latest FluWatch report, released Friday.

Last year, there were far fewer cases, with 8,976 reported by the end of the first week of January 2017.

H3N2, which is the dominant flu in both Canada and the U.S., is prone to mutation, which can make the vaccine against it less effective — even though it appears the virus strain was correctly predicted. Experts, including Canada's chief public health officer, have said that, although it's too early to tell for sure, the H3N2 component of this year's vaccine may have mutated during the manufacturing process, making it less effective.

Tran said it's too early to make a call on the vaccine's effectiveness, but he still advocated that Hamiltonians get their flu shot, even though it takes two weeks to be fully effective.

"I still think it's a good idea to get it, as we might not be at the peak yet," he said. 

adam.carter@cbc.ca

With files from Nicole Ireland