Over the past month, thousands of Canadians have caught and recovered from the Omicron variant of COVID-19, with Canada’s chief public health officer saying cases have likely peaked nationwide.
People who have received two doses of the vaccine, a third dose or booster shot and a previous COVID-19 infection have more protection against the virus than ever before. But does the antibody cocktail of three doses and infection-based immunity make you bulletproof against another infection?
While data on re-infections of the Omicron variant is limited, experts say most people will have a grace period during which they are unlikely to become sick with the same variant again.
But they caution that immunity wanes with time, and the potential for more variants to emerge means the population-level immunity earned during the Omicron wave won’t remain stable.
“If you’ve had Omicron, you’re probably good for a minimum of three months before you’d really have to worry about catching it again, unless the next variant is super, super different than something we’ve seen before,” said Bruce Mazer, professor of pediatrics at McGill University and associate scientific director of the COVID Immunity Task Force.
“It really depends on how the virus mutates. If the virus stays the same as the ones that we’ve been vaccinated against, or Omicron, then you’ve got good protection for a while. Unfortunately if it mutates again then we don’t know.”
Samir Sinha,director of geriatrics at Sinai Health System and the University Health Network, said the strength of immune response will depend on a person’s age and overall health. The very old, very young, and immunocompromised will have weakened responses, and the degree to which a person became ill may also come into play.
“Sometimes depending on the severity of your infection, it might also translate into the immune response that you might create. If someone had a severe infection that might have been prolonged as well, they might have a much more robust immune response and potentially a higher level of immunity,” said Sinha.
Experts say it is crucial to get your third dose of vaccine even if you already have some degree of natural immunity from a previous infection. (Ben Nelms/CBC)
“But you can’t just tell by that — there are so many different factors to determine what your level of immunity is and how long that immunity will last.”
For that reason, it’s crucial to get your booster or third dose of vaccine even if you already have some degree of infection-based immunity from a previous infection. A third dose is a supplementary dose administered to people with conditions that make them more vulnerable to the coronavirus, whereas a booster is given to the general population as a form of re-vaccination some time after their initial doses.
“Getting vaccinated is more likely to ensure you a more consistent and stronger immune response or level of immune protection against potentially getting infected in the future,” he said, adding the timing of future waves will also depend on how much of the population experiences waning immunity from their most recent vaccines.
“We started to see in the fall an uptick in the number of cases in part because that was also the time that we were starting to see that second dose immunity starting to wane.”
How protected am I against other variants?
No one knows with certainty which COVID-19 variant they are infected with, but if you got sick in the past month, there’s a high probability it was with the highly transmissible Omicron variant.
Mazer said both the vaccines and previous variants look very different from Omicron, which has at least 36 changes in its spike protein — the part of the protein people are vaccinated against. He said these features are what allowed Omicron to infect people previously vaccinated, but that Omicron also has features similar enough to previous variants to afford some immune protection.
“You should have a boost of your immunity against all the current types that we’ve seen,” Mazer said.
Still, Mazer and Sinha warn, with so many people getting sick, and much of the world still unvaccinated, the risk of new variants that could overcome current levels of immunity remains.
Already, the rise of Omicron subvariant BA.2, is raising questions about the possibility of re-infection after an Omicron case, though it is not currently considered a variant of concern.
“We’re hoping that our natural and vaccine level immunity that we have achieved with Omicron will support us with whatever thing comes next,” said Sinha.
“There’s a whole lot of variables here that wouldn’t allow people to rest on their laurels and say, ‘I’m done with COVID.’ A lot more can happen until we get the whole world vaccinated.”
Toronto-based general practitioner Peter Lin said while some people may feel “superhuman” after three doses of vaccine and a previous infection, he warns against throwing caution to the wind, especially with the risk of long COVID and the possibility of passing it on to someone more vulnerable.
“If you were infected with Delta or Omicron or the original virus, assume you can still get infected with junior,” he said, referring to the Omicron subvariant BA.2.
“You have some defences, so you’re not going to get very sick, but you could pick up junior and grow it in your nose and pass it on to someone unvaccinated, like kids.”
Lin said the more people test positive for COVID-19, the likelier it is that new variants able to evade infection-based and vaccine-derived immunity will arise and spread.
“Not getting infected is how we get out of this pandemic. The way out is not to let everyone get infected.”
The Canadian government says it will donate up to 200,000 vaccine doses to fight the mpox outbreak in Congo and other African countries.
It says the donated doses of Imvamune will come from Canada’s existing supply and will not affect the country’s preparedness for mpox cases in this country.
Minister of Health Mark Holland says the donation “will help to protect those in the most affected regions of Africa and will help prevent further spread of the virus.”
Dr. Madhukar Pai, Canada research chair in epidemiology and global health, says although the donation is welcome, it is a very small portion of the estimated 10 million vaccine doses needed to control the outbreak.
Vaccine donations from wealthier countries have only recently started arriving in Africa, almost a month after the World Health Organization declared the mpox outbreak a public health emergency of international concern.
A few days after the declaration in August, Global Affairs Canada announced a contribution of $1 million for mpox surveillance, diagnostic tools, research and community awareness in Africa.
On Thursday, the Africa Centres for Disease Control and Prevention said mpox is still on the rise and that testing rates are “insufficient” across the continent.
Jason Kindrachuk, Canada research chair in emerging viruses at the University of Manitoba, said donating vaccines, in addition to supporting surveillance and diagnostic tests, is “massively important.”
But Kindrachuk, who has worked on the ground in Congo during the epidemic, also said that the international response to the mpox outbreak is “better late than never (but) better never late.”
“It would have been fantastic for us globally to not be in this position by having provided doses a much, much longer time prior than when we are,” he said, noting that the outbreak of clade I mpox in Congo started in early 2023.
Clade II mpox, endemic in regions of West Africa, came to the world’s attention even earlier — in 2022 — as that strain of virus spread to other countries, including Canada.
Two doses are recommended for mpox vaccination, so the donation may only benefit 100,000 people, Pai said.
Pai questioned whether Canada is contributing enough, as the federal government hasn’t said what percentage of its mpox vaccine stockpile it is donating.
“Small donations are simply not going to help end this crisis. We need to show greater solidarity and support,” he said in an email.
“That is the biggest lesson from the COVID-19 pandemic — our collective safety is tied with that of other nations.”
This report by The Canadian Press was first published Sept. 13, 2024.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
HALIFAX – The Nova Scotia government says it could be months before it reveals how many people are on the wait-list for a family doctor.
The head of the province’s health authority told reporters Wednesday that the government won’t release updated data until the 160,000 people who were on the wait-list in June are contacted to verify whether they still need primary care.
Karen Oldfield said Nova Scotia Health is working on validating the primary care wait-list data before posting new numbers, and that work may take a matter of months. The most recent public wait-list figures are from June 1, when 160,234 people, or about 16 per cent of the population, were on it.
“It’s going to take time to make 160,000 calls,” Oldfield said. “We are not talking weeks, we are talking months.”
The interim CEO and president of Nova Scotia Health said people on the list are being asked where they live, whether they still need a family doctor, and to give an update on their health.
A spokesperson with the province’s Health Department says the government and its health authority are “working hard” to turn the wait-list registry into a useful tool, adding that the data will be shared once it is validated.
Nova Scotia’s NDP are calling on Premier Tim Houston to immediately release statistics on how many people are looking for a family doctor. On Tuesday, the NDP introduced a bill that would require the health minister to make the number public every month.
“It is unacceptable for the list to be more than three months out of date,” NDP Leader Claudia Chender said Tuesday.
Chender said releasing this data regularly is vital so Nova Scotians can track the government’s progress on its main 2021 campaign promise: fixing health care.
The number of people in need of a family doctor has more than doubled between the 2021 summer election campaign and June 2024. Since September 2021 about 300 doctors have been added to the provincial health system, the Health Department said.
“We’ll know if Tim Houston is keeping his 2021 election promise to fix health care when Nova Scotians are attached to primary care,” Chender said.
This report by The Canadian Press was first published Sept. 11, 2024.
ST. JOHN’S, N.L. – Newfoundland and Labrador‘s chief medical officer is monitoring the rise of whooping cough infections across the province as cases of the highly contagious disease continue to grow across Canada.
Dr. Janice Fitzgerald says that so far this year, the province has recorded 230 confirmed cases of the vaccine-preventable respiratory tract infection, also known as pertussis.
Late last month, Quebec reported more than 11,000 cases during the same time period, while Ontario counted 470 cases, well above the five-year average of 98. In Quebec, the majority of patients are between the ages of 10 and 14.
Meanwhile, New Brunswick has declared a whooping cough outbreak across the province. A total of 141 cases were reported by last month, exceeding the five-year average of 34.
The disease can lead to severe complications among vulnerable populations including infants, who are at the highest risk of suffering from complications like pneumonia and seizures. Symptoms may start with a runny nose, mild fever and cough, then progress to severe coughing accompanied by a distinctive “whooping” sound during inhalation.
“The public, especially pregnant people and those in close contact with infants, are encouraged to be aware of symptoms related to pertussis and to ensure vaccinations are up to date,” Newfoundland and Labrador’s Health Department said in a statement.
Whooping cough can be treated with antibiotics, but vaccination is the most effective way to control the spread of the disease. As a result, the province has expanded immunization efforts this school year. While booster doses are already offered in Grade 9, the vaccine is now being offered to Grade 8 students as well.
Public health officials say whooping cough is a cyclical disease that increases every two to five or six years.
Meanwhile, New Brunswick’s acting chief medical officer of health expects the current case count to get worse before tapering off.
A rise in whooping cough cases has also been reported in the United States and elsewhere. The Pan American Health Organization issued an alert in July encouraging countries to ramp up their surveillance and vaccination coverage.
This report by The Canadian Press was first published Sept. 10, 2024.
