The risk posed by monkeypox is low, but nearly everyone in Canada is susceptible to it because routine smallpox vaccination ended decades ago, senior public health officials said Friday.
Monkeypox is a rare disease that comes from the same virus family as smallpox. This virus causes smallpox, which the World Health Organization declared eradicated worldwide in 1980. It is also related to the vaccinia virus used in the smallpox vaccine.
The Public Health Agency of Canada, which is investigating about two dozen possible cases of monkeypox in addition to two confirmed cases in Quebec, says it is spread through prolonged close contact. This includes direct contact with respiratory droplets, bodily fluids, or wounds of an infected person, and is not highly contagious in a typical social setting.
The BC Center for Disease Control said Friday it was not investigating any suspected cases or possible contacts of monkeypox in the province after ruling out two potential contacts.
Canada’s chief public health officer, Dr Theresa Tam, said the federal public health agency did not know how far the disease had spread in the country.
Monkeypox is generally milder than smallpox and can cause fever, headache, muscle aches, exhaustion, swollen lymph nodes and lesions all over the body.
There is worldwide evidence that smallpox vaccines can provide protection against monkeypox.
But Canada stopped routinely vaccinating people against smallpox in 1972.
Tam’s assistant, Dr Howard Njoo, said that means everyone is susceptible to monkeypox.
“I would say that generally the whole population is susceptible to monkeypox,” Njoo said on Friday.
Canada maintains a small stockpile of smallpox vaccine in case of a biological incident, such as a laboratory exposure.
A handful of cases in the UK prompted that country to start offering the vaccine to health workers and close contacts of confirmed cases.
Tam said Canada is considering a similar strategy.
“Quebec had some interest in terms of contacts, so that’s being discussed right now, but of course we need to know some of the epidemiology as quickly as possible,” Tam said.
She did not say how many doses of smallpox vaccine Canada has on hand, citing security concerns.
Public Services and Procurement Canada issued a tender last month to purchase 500,000 doses of the Imvamune smallpox vaccine on behalf of the Public Health Agency of Canada from 2023 to 2028.
“While smallpox is currently considered eradicated, PHAC procures a stockpile of vaccines to immunize Canadians against smallpox should a risk arise when smallpox is intentionally or unintentionally released,” the RFP states.
Health Canada has also approved this vaccine, from Danish biotechnology company Bavarian Nordic, for use in the prevention of monkeypox.
The company announced on Thursday that it had reached an agreement with an unnamed European country to supply its vaccine in response to cases of monkeypox.
There is still a sense of mystery surrounding the sudden outbreak of the virus in Canada, the United States, Australia and several parts of Europe.
“Few of these people are connected to travel to Africa where the disease is normally seen, so it is unusual. It is unusual for the world to see so many cases reported in different countries outside of Africa,” Tam said. .
Canadian health systems are casting a wide net in their search for more cases, she said, because not enough is known about why the virus is suddenly surging around the world.
“There were probably hidden chains of transmission that could have been going on for a number of weeks, given the kind of global situation we’re seeing right now,” she said.
Njoo said global public health authorities need to be open to the idea that monkeypox is changing and transmission may also have changed.
For now, samples from suspected cases are sent to the National Microbiology Laboratory in Winnipeg, but PHAC is working with the provinces to implement more local diagnostics.
– Laura Osman, The Canadian Press