TORONTO -- Life in Canada has been disrupted in extraordinary ways in an attempt to halt the spread of COVID-19.

Schools, restaurants and public places have been ordered shut in various parts of the country. Even the border has been closed to many would-be travellers.

The speed and scope of preventative measures have caught many Canadians off-guard, but to public health experts such as Suzanne Sicchia, they were entirely predictable -- and not strict enough to accomplish their goal.

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"I do believe more will have to close in the coming weeks," Sicchia, an associate professor at the University of Toronto's Dalla Lana School for Public Health, told CTVNews.ca Wednesday via telephone.

"I'd be surprised if non-essential services remain open -- and I think we should anticipate that happening for more than a week or two."

Many of the measures were introduced with an implication that they would be short-term. Schools were told to close for a few weeks. States of emergency were given end-dates in the not-too-distant future.

On Tuesday, Prime Minister Justin Trudeau hinted for the first time that Canadians might have to brace themselves for longer disruptions.

"We don’t know exactly how long this is going to take, whether it [will] take weeks or months," he said.

Other parts of the world seem to be leaning more toward months. Ireland Prime Minister Leo Varadkar, whose country has seen roughly as many COVID-19 cases as Canada, warned Tuesday that disruptions to everyday life there could last into the summer.

In the U.S., Surgeon-General Jerome Adams said Wednesday that the government's current recommendation of a 15-day social distancing period is "likely not going to be enough" to stop the virus.

"I think you'll start to see the language [in Canada] shift to that, to prep the public psychologically for extended measures," Sicchia said.

HOW LONG COULD IT LAST?

More alarmingly, a paper published Monday by British researchers argues that preventing COVID-19 cases from completely overwhelming health-care systems may require some isolation and social distancing measures to remain in place for well over a year.

"To avoid a rebound in transmission, these policies will need to be maintained until large stocks of vaccine are available to immunise the population -- which could be 18 months or more," reads the paper from Imperial College London.

The researchers based these conclusions on models of COVID-19's spread through the U.K. and U.S., but said their findings apply to other countries as well.

Their calculations assume schools remain open, while people reduce their contact with others in their household and coworkers by 25 per cent, and everyone else by 75 per cent. Even three months of this level of social distancing would be expected to cut the number of deaths in the population in half, they said.

Current guidance in Canada goes beyond what the researchers used for their models. In other words, by following the current advice, Canadians could lessen the impact beyond even the best-case scenario outlined in this paper.

Canada's chief public health officer, Dr. Theresa Tam, echoed Trudeau's suggestion of a long-term threat Wednesday while speaking to reporters.

"This virus is going to be with us for some time. It will not be eradicated from the world in months," she said.

"We will need to be prepared for another wave, potentially."

The combination of increasing caseloads and uncertainty over the future could well lead to more significant public disruptions than have been put in place thus far.

"I think we're evolving towards that. I think it's important that people recognize that we are going to have a more restrictive lifestyle," Dr. Abdu Sharkawy, an infectious disease specialist, told CTV News on Wednesday.

Tam emphasized the importance of following public health authorities' recommendations to try to keep the virus spreading as slowly as possible, preventing a sudden spike in hospitalizations -- the same scenario the Imperial College researchers say can best be avoided through long-term social distancing measures.

THE WAITING GAME

The research into COVID-19 is evolving rapidly. It takes time for tested science to catch up to the situation on the ground. But it also takes time for even the latest understanding of the situation on the ground to catch up to reality.

Experts say closures and other actions taken in response to the virus aren't reflected in diagnosis and death numbers for two to three weeks.

"When you’re dealing with an emerging infectious diseases outbreak, you are always behind where you think you are if you think that today reflects where you really are," Dr. Anthony Fauci, a member of the U.S. COVID-19 task force, said Monday at a press briefing.

This makes it difficult for governments to plan incremental measures. This week's numbers reflect COVID-19's progress at a time when Canada was taking essentially no measures to stop it. Tuesday's announcement of a Canada-U.S. border closure won't be reflected in the data until April.

With so much lag time and so much uncertainty about the immediate big picture, experts say the best advice for Canadians is simple: Follow the recommendations of public health authorities. Wash hands vigorously. Keep others at two arms' length, even at home -- and only leave home if absolutely necessary.

"If you don't have to go out, just don't," Sicchia said.

"Even if [you]'re young and well and able-bodied and not in any of the risk categories ... [you] could spread to other people by not observing those measures. There's actually no way around this. This is something that we must all take seriously."

For governments, taking it seriously has often included recommending a maximum number of people for gatherings. Most provinces have currently set that number at 50, but Sicchia describes that as "completely arbitrary" -- and irrelevant to the best practice, which is simply to stay away from others.

"I don't know many public health officials who ... would say there's some magic number," she said.