November 27, 2024

Canadians should weigh risk of rare blood clots from Johnson & Johnson vaccine with COVID-19 risk, NACI says

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The Johnson & Johnson vaccine is now recommended for all Canadians 30 years of age and older, but officials say to weigh the risk of rare but potentially serious blood clots that can occur from the vaccine with COVID-19 levels in the community — or hold out for another shot altogether.

The National Advisory Committee on Immunization (NACI) said Monday that while the Johnson & Johnson vaccine will soon be distributed across Canada, it’s up to Canadians in that age group to decide whether they should take it or wait for an mRNA vaccine such as Pfizer-BioNTech or Moderna.

Health Canada approved the Johnson & Johnson vaccine in March and updated its labelling last week to acknowledge the risk of a rare but serious blood-clotting condition connected to the shot known as vaccine-induced immune thrombotic thrombocytopenia (VITT).

“NACI weighed the benefits of the Janssen vaccine in saving lives and protecting populations against serious complications of COVID-19 against the risk of developing VITT,” said NACI vice-chair Dr. Shelley Deeks said during a news conference Monday. 

“At this time, based on the current evidence, NACI recommends that similar to the AstraZeneca vaccine, the Janssen vaccine may be offered to individuals 30 years of age and over without contraindications if the individual prefers an earlier vaccine rather than waiting for an mRNA vaccine and if the benefits outweigh the risks.”

The move followed a brief pause of the Johnson & Johnson vaccine in the U.S. to investigate reports of clots, which NACI officials said Monday have occurred in 17 of the roughly eight million Americans who have received the shot.

a man and a woman looking at the camera: A health worker wears a protective face mask and gloves as she gives a Johnson & Johnson COVID-19 vaccine to a woman inside a tent in Krakow, Poland, on Saturday. NACI says that while the Johnson & Johnson vaccine will soon be distributed across Canada, it's up to Canadians to decide whether they should take it or wait for an mRNA vaccine such as Pfizer-BioNTech or Moderna. © Omar Marques/Getty Images A health worker wears a protective face mask and gloves as she gives a Johnson & Johnson COVID-19 vaccine to a woman inside a tent in Krakow, Poland, on Saturday. NACI says that while the Johnson & Johnson vaccine will soon be distributed across Canada, it’s up to Canadians to decide whether they should take it or wait for an mRNA vaccine such as Pfizer-BioNTech or Moderna. Risk in context

VITT has also been reported with the AstraZeneca-Oxford COVID-19 vaccine in Canada, and like the J&J vaccine, it uses a similar adenovirus vector technology, which has led to unproven speculation that the rare condition could be connected to the vaccine platform.

“What we’re saying, and what we’ve been saying all along, is that the mRNA vaccines are the preferred vaccines,” said Deeks. “Yet given the epidemiology, the viral vector vaccines are very effective vaccines, but there is a safety signal, a safety risk.”

NACI says VITT occurs at a rate of about one in 100,000 people vaccinated with the AstraZeneca vaccine, with a mortality rate of about 40 per cent, although more research is needed — and that number is subject to change.

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“You can’t ignore the VITT risk,” said Dr. Isaac Bogoch, an infectious diseases physician and member of Ontario’s COVID-19 vaccine task force. 

“But we have to put it in the context of a third wave. We have more COVID-19 than ever before in Canada, with health care systems that are stretched beyond capacity, so you have to at least give people an opportunity to make an informed decision to take this or not.” 

Though extremely rare, VITT is much more severe than a typical blood clot because it can cause cerebral venous sinus thrombosis (CVST), where veins that drain blood from the brain are obstructed and can potentially cause fatal bleeding.

Canada has reported seven confirmed cases of VITT following the AstraZeneca vaccine out of more than 1.1 million doses administered. One death was reported in Quebec on Saturday, when a 54-year-old woman died of CVST in a Montreal hospital after receiving the AstraZeneca shot on April 9.

‘It’s going to be challenging’

Bogoch said it wouldn’t be fair to Canadians who want to take the Johnson & Johnson vaccine to hold it back from the population entirely on account of VITT but said there was “room for improvement” for NACI officials to help Canadians navigate their individual decision making around risk.

“Many people are living in health care systems that are stretched to or beyond capacity with more COVID-19 than ever before, and here’s a life raft,” he said.

“I think there are a lot of people that would still take it and, of course, the alternative is you can wait for an mRNA vaccine, but be careful.” 

Dr. Michael Gardam, an infectious diseases specialist and the acting CEO of Health PEI, said the NACI recommendations make it harder to expect that Canadians will want to line up to get the Johnson & Johnson vaccine.

“Some people are going to be perfectly accepting of the risk, and the risks are very miniscule, but others won’t and they’ll wait and that’s going to delay vaccination for a proportion of the population,” he told CBC News. 

“If you got a very high rate of COVID where you live then the benefit of any vaccine clearly hugely outweighs any small risks.”

Bogoch said the updated NACI guidelines around the Johnson & Johnson vaccine could cause hesitation among some Canadians but that the similar update to AstraZeneca guidelines didn’t stop many Canadians from getting it. 

“People may be reluctant to take it because of that, and that’s something we’re gonna have to contend with, and it’s going to be challenging,” he said. 

“We have to remember, too, we gave AstraZeneca, which has a risk of VITT, to people over the age of 40 and Gen X were storming the gates to get access.” 

NACI also announced Monday that mRNA vaccines, such as Pfizer-BioNTech and Moderna, are preferred in pregnant women and that Canadians who have previously been infected with COVID-19 should still receive two doses of a vaccine rather than one. 

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