Once the Canadian epicentre of monkeypox, Montreal has nearly eradicated the virus from its territory, according to health experts.

However, Montreal's public health department (DSP) warns that tourists and other visitors can still import cases -- and it's still unclear how long the vaccine will remain effective.

Dr. Geneviève Bergeron, head of health emergencies and infectious diseases at the Montreal DSP, is cautiously optimistic.

"We have certainly seen a sharp decline in the last few weeks," she confirmed in a recent interview.

Dr. Réjean Thomas, president of l'Actual, a clinic specializing in sexually transmitted and blood-borne infections, reports seeing nearly a dozen people a day who thought they had the disease. Now, these cases are few and far between.

His clinic has treated a total 125 monkeypox patients -- more than a quarter of all cases in Montreal since the first was detected on May 12.

But Thomas says the future remains uncertain; he recently saw a monkeypox patient vaccinated in July.

"So that's the big question: how effective will the vaccine be and for how long?" he said.

According to Dr. Bergeron, studies are underway to determine how long Imvamune, a smallpox vaccine approved for use against monkeypox, will provide protection.

The vaccine is available to anyone who believes they were exposed to the virus and to those whose sexual behaviours may increase their risk of contraction.

Public health officials are now encouraging people who have received a first dose of the monkeypox vaccine to get a second.

"We know that one dose provides good protection, a second dose provides even better protection," said Bergeron.

So far, about 30,000 people have received a shot of the monkeypox vaccine in Quebec.

Last week, Quebec Public Health Director Dr. Luc Boileau said roughly 6,000 people have received a second dose, and that only one case had been detected in the province within the last two weeks.

Quebec is not the only place where monkeypox cases are declining. In Ontario, where the virus's trajectory has followed a similar pattern, the chief medical officer said in mid-October that he was considering declaring the epidemic over.

The World Health Organization (WHO) reports that the number of new cases of monkeypox in several countries -- including Canada, the United Kingdom and Italy -- decreased by more than 50 per cent in the last week of October compared to the previous week.

Several other countries, including France and the U.S., have seen smaller declines, but the number of new cases continues to rise in other parts of Europe and Central and South America.

Bergeron notes that the cause of the decline is unclear, but in her opinion, vaccination likely played a role.

"We've seen overall fewer cases in Montreal than in other countries and jurisdictions, so I think the vaccination campaign has helped," she said.

Public health officials knew there was a high risk of stigmatizing people, she noted, therefore working closely with the LGBTQ+ community to craft the message around vaccination.

Christian Tanguay, executive director of the Montreal LGBTQ+ Community Center, was concerned people would not get vaccinated because they feared stigmatization for having multiple partners.

But seeing three people he knew contract the virus motivated him to get the vaccine quickly and encourage others to do the same. 

This report by The Canadian Press was first published in French on Nov. 7, 2022.