With the polio virus making a comeback in some parts of the world, many Canadians may be wondering how to protect themselves against the disease. According to Canada’s top doctor, getting vaccinated is the best and most effective way to do so.
“When it comes to vaccine-preventable illnesses, the vaccine against polio is very effective,” said Dr. Theresa Tam, Canada’s chief public health officer, during a virtual health update on Friday.
“The key is to get up-to-date with your vaccination…The vaccine coverage is quite high for polio in Canada, but I don’t know what happened during the pandemic. I hope people are getting caught up before school or travel,” she added.
U.S. officials reported in early August that an unvaccinated American in New York, in Rockland County, north of the city was diagnosed with the country’s first case of polio in nearly a decade.
No other cases have been reported and the U.S. Centers for Disease Control (CDC) are urging parents to get their children vaccinated against the potentially deadly disease.
That discovery came shortly after British health authorities reported finding evidence that the virus has spread in London but no cases have been reported in people so far.
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U.K.’s National Health Service says investigations into community transmission are ongoing and that children aged one to nine in London have been made eligible for booster doses of a polio vaccine as of Aug. 10.
Even though Health Canada has not recorded a case of the virus in more than 25 years, Dr. Tam explained during the health update that when it comes to vaccine-preventable illnesses, the issue is under immunization, which can often lead to cases re-emerging.
Poliovirus is highly contagious and usually causes no symptoms or mild symptoms such as low-grade fever, malaise, nausea, diarrhea and sore throat. Illnesses are most common in infants and young children, but adults who are not fully immunized can also become sick. The virus attacks the nervous system, with one to five per cent of infections causing meningitis and less than one per cent resulting in paralysis.
People who are unvaccinated or incompletely vaccinated are at the greatest risk of paralysis from polio.
Canada’s routine childhood vaccine schedules include injectable polio vaccines before the age of two years and a booster at four to six years. The injectable form of the vaccine is inactivated and does not transmit the virus person-to-person.
Several experts on climate change and infectious disease have agreed that a warming planet will likely lead to increased risk for the emergence of new viruses.
In a new study published in the journal Nature Climate Change, researchers looked through the medical literature of established cases of illnesses and found that 218 out of the known 375 human infectious diseases, or 58 per cent, seemed to be made worse by one of 10 types of extreme weather connected to climate change.
These new and re-emerging infectious diseases include monkeypox, malaria, hantavirus, cholera, anthrax, and the Langya virus detected in China.
Tam too, highlighted the possibility of increased emergence of viruses caused by climate change.
Emerging infectious diseases that are mostly transmitted from animals to humans are expected to rise because of climate change and global travel, cautioned Tam. However, vaccination can help counter the transmission.
“We do need to prepare, do the research and not ignore them…Monkeypox as we know has been knocking on our doors for quite some time and has now found a way to get into the human population,” said Tam.
Monkeypox is primarily transmitted through prolonged close contact with an infected person and the majority of cases reported in the current outbreak involve men who had intimate sexual contact with other men, according to the WHO.
Monkeypox infections have also been found in rodents and other wild animals, which can spread the virus to humans, the World Health Organization (WHO) says.
In Canada, as of Aug. 19, 1,168 monkeypox cases have been reported across the country, with Ontario leading the case count with 571 infections, followed by Quebec with 453.
To date, there have been 30 hospitalizations, but no deaths in Canada.
“Vaccines have been researched and we have some of that, maybe not enough for the global need but at least all the research has been done prior,” said Tam.
As more infectious diseases emerge, she says global collaborations and more support is needed to look at the risks of re-emergence of viruses that may lead to the next pandemic.
In the meantime, plans are underway to sift through Canadian sewage to test for and measure new health threats like monkeypox and polio after the success this testing has achieved in detecting COVID-19, according to Tam.
Experts at the National Microbiology Lab have discovered a promising approach to detect monkeypox in wastewater and will use the infrastructure developed during the pandemic to look for it, she added.
— with files from The Canadian Press and The Associated Press