Public health officials are warning that COVID-19 infections may increase in severity as the latest subvariant known as Kraken spreads in Canada.

Public health says Niagara had the highest number of cases from December 4th to December 31 with 18 residents testing positive for the Kraken subvariant.

However, Public Health Ontario’s December data is the latest we have, “so we don’t actually know what the current situation is because those results that are collected from tests this week are still going to be processed for a couple more weeks before we know the variants,” Dr. Hirji said.

Last month in Hamilton, Kraken, which is the XBB.1.5 variant, made up only 0.3 per cent of cases.

Public Health Ontario data also showed that Haldimand, Norfolk, and Brant County had the highest number of infections in the province.

Infectious disease specialist Dr. Zain Chagla says Kraken’s high presence in areas surrounding Hamilton stems from its presence in the eastern United States, “the first detections of XBB.1.5 were in New York state, so not unsurprising that the areas bordering with New York state are the ones seeing the earliest transmission.”

Dr. Chagla says he doesn’t think Kraken is going to be as bad as previous variants, “I think from our early indication from the U.S., more transmission, more pressure, but not certainly at the level of prior explosions like when Omicron came about.”

The federal government provided it’s first COVID-19 update of the year on Friday. Dr. Theresa Tam says, “while XBB variants are expected to increase in Canada, it is not known whether they will become the dominant lineage. Nationally, the absolute number of cases is not surging at this time nor is there evidence of increased severity with this, or other new variants.”

WATCH: Minister of Health provides national COVID-19 update at 10 a.m.

The federal government says Canadians should continue to get booster doses in response to subvariants.