The next two weeks are going to be difficult ones in Canada. The number of confirmed coronavirus infections, and the number of deaths caused by COVID-19, are likely to rise rapidly.

There are multiple reasons for this. One is that the virus is now spreading via community transmission, rather than being traced solely to people who brought it home from other countries.

Another is that the provinces are testing more people every day – a critical effort, but which will make the numbers seem even more stark.

But the third and most important reason is timing. Positive cases discovered this week are the result of infections picked up two weeks ago, or more.

Two weeks ago Monday, the federal government had only just asked Canadians to self-isolate for 14 days after returning from overseas, and our borders were still open to non-essential travel.

Two weeks ago Monday, Ontario and Quebec had just closed their public schools. Ontario and British Columbia were, respectively, still one and two days away from declaring states of emergency. Businesses, including restaurants and bars, were still operating in all provinces. Community centres, libraries, parks and playgrounds were still open in Toronto and Vancouver.

And in the week that began on Monday, March 16, more than one million Canadians returned from overseas.

The near-certain increase in the number of confirmed infections this week is, in part, an inevitable result of this country’s failure to take dramatic action until mid-March.

Given the incubation period of the coronavirus, and the 14 days required to ensure a returning traveller is not shedding the pathogen, the current spike in cases is not surprising. A virus whose stealthy propagation was mostly unseen two weeks ago is making itself known right on schedule.

But Canadians should not lose heart. Their commitment to self-isolation, and the difficult and painful sacrifices so many are making right now, should begin to deliver their first dividends soon. Some signs of that were visible this week.

In B.C., there is evidence that social-distancing measures have begun to slow the spread of the virus in that province. There are similar hopeful signs in Washington State.

And we know the measures worked in China and South Korea, along with testing and tracing. Both countries appear to have flattened the curve on their infection rates.

In Canada, flattening the curve is, to a great degree, now in the hands of Canadians themselves. It is vital that we all do our part by remaining isolated at home as much as possible over the next few weeks.

And yet there is reason to worry that following the rules is still not universal. An online survey of 2,000 adults by Innovative Research Group found that, among people recently returned from overseas or living with someone who had travelled abroad, most had broken their 14-day quarantine by doing things like going to the grocery store. The survey was conducted March 23-26.

On Monday, Ontario Premier Doug Ford said his government may yet have to order people in the province to stay home, under threat of penalty, because too many aren’t doing so voluntarily. In Toronto, people caught using closed park facilities will now face fines.

With all that we know, it is unconscionable at this point to act as though the pandemic doesn’t involve you, or to assume that your individual actions aren’t risky.

You only have to look at Newfoundland, where a single person who returned to the island infected at least 68 people at a St. John’s funeral home. Or at a seniors’ residence in Bobcaygeon, Ont., where nine people have died – including seven over the weekend – and 34 staff members are infected.

This is a virus that loves a crowd. Our self-isolation measures are critical to stopping it. They may already have begun to be effective; we will know more in the coming weeks.

But the virus could also continue to feast on the indifference of a small but significant number of people who consider themselves above the fray, or who fall back on the ill-informed hope that their actions won’t cause harm.

The next two weeks will be difficult but, unless people keep their distance, things will get much worse in the two after that.

For the good of everyone, stay home.