Production delays and a late determination by the global authority on public health has led to delays in deliveries of flu vaccines, according to Ontario's Health Minister.
Christine Elliott says the World Health Organization was roughly a month late in identifying what one of the dominant strains of flu would be for the upcoming flu season.
That left companies that produce the vaccines to scramble to keep up with demand around the world.
It comes as bellwether countries like Australia have grappled with a particularly severe start to the flu season.
Elliott says Ontario took steps early to get ahead of this problem by ordering hundreds of thousands of extra doses of the standard flu vaccine.
"We've been making plans for a number of months to be ready for flu season," Elliott says.
"We will be ready to vaccinate people when the time comes."
However, shipments of the extra-strength vaccine typically reserved for the elderly and people with health complications has been slow to arrive.
"The high-dose flu vaccines will be coming in a little bit later than we anticipated because there are anticipated shortages around the world," Elliott says.
"This isn't something new that's just in Ontario."
Officials with the Health Ministry say those high-dose flu shots are currently being administered at places like hospitals and long-term care homes.
They say the expectation is that flu shots will be available across the province by the end of the month.