Canada has delayed second doses of COVID-19 vaccines by up to four months — the longest interval recommended by a country so far — but has yet to provide any new guidance to Canadians on what they can or can't do while waiting for the second shot.
The National Advisory Committee on Immunization (NACI) changed its guidelines earlier this month on the recommended time between doses of COVID-19 vaccines from three weeks to four months.
NACI said it based its revised guidelines on emerging real world evidence and the reality of Canada's limited supply of COVID-19 vaccines, although there is no research yet on the long-term effect the delay could have on immunity to the coronavirus disease.
The decision was also informed by findings from the British Columbia Centre for Disease Control that determined that one dose of the vaccine was actually more effective than clinical trials had initially shown.
NACI said if second doses were stretched to four months across the country, close to 80 per cent of Canadians over 16 could get at least one shot by the end of June.
But Canada's chief science adviser, Mona Nemer, has said the decision to delay second doses amounted to a "population level experiment."
The United Kingdom has delayed second doses by up to three months, but no other country is known to have delayed them by up to four months. Spokespeople from Pfizer and Moderna said they recommend sticking with intervals of three and four weeks for their respective vaccines as studied during clinical trials.
What can Canadians do after being vaccinated?
Many Canadians are wondering what they can do after getting vaccinated and if they can safely see their families, other vaccinated people or generally feel less at risk from COVID-19 after a year under strict public health measures.
But the recommendations still haven't been updated weeks after the change was made — meaning Canadians could be tempted to make up their own rules in the interim.
The U.S. Centers for Disease Control and Prevention released guidelines on March 8 for fully vaccinated individuals, saying they can safely meet indoors without masks or physically distancing with others who had received both shots.
The CDC also said those who have had both shots can visit with unvaccinated people from a single other household who are at "low risk for severe COVID-19," as well as skipping quarantine and testing if exposed to COVID-19 without showing symptoms.
But unlike Canada, the U.S. hasn't delayed second doses by up to four months and answers to those questions have been harder to come by for Canadians weeks after guidelines changed and close to 5 million doses administered.
Canada's Chief Public Health Officer Dr. Theresa Tam said during a news conference Tuesday that the issue is being actively discussed with the provinces and territories and that while new guidance is coming, the country is in the "early days" of its vaccine coverage.
"For now, the key message is that everyone needs to keep up with their personal protective measures which are wearing a mask, handwashing, watching your distance and avoiding closed, crowded conditions," she said.
"I think as more and more people get vaccinated I would expect the advice to evolve as we go along, but it's a little bit too early."
Tam said the spread of coronavirus variants across Canada amid already high levels of community transmission should factor into "local decisions" on what public health measures need to be put in place or lifted for vaccinated individuals.
She provided no timeframe for when Canadians can expect to see new guidance from the Public Health Agency of Canada on what they can and can't do after being vaccinated.
Guidelines for Canadians with only one dose even less clear
And what about guidelines for Canadians who have only had one dose?
"It's maybe not clear to the general public, but it should be clear that you're only fully vaccinated after two doses," said Prof. Alyson Kelvin, an assistant professor at Dalhousie University and virologist at the Canadian Center for Vaccinology.
"I can completely sympathize that it's been a long haul for everybody, but it's really important that we continue with those public health measures until we have a low level of virus transmission within the community."
She says until Canada's hardest-hit regions have significantly lowered their rates of community transmission, Canadians will have to continue practicing physical distancing, proper hand hygiene, avoiding crowds and wearing masks in public.
"You're still at risk even though you're fully vaccinated," says Kelvin, who is also evaluating Canadian vaccines with the VIDO-InterVac lab in Saskatoon.
"Even with two doses, you can still be infected and transmit the virus — you just might not be as ill as somebody who wasn't vaccinated."
Until Canada has a large proportion of vaccinated people across the country who can help decrease overall COVID-19 levels, Kelvin says it makes sense for hard-hit regions to hold off on relaxing public health measures.
Dr. Nathan Stall, a geriatrician at Mount Sinai Hospital in Toronto, says communication from public health officials on what people can do after getting a COVID-19 vaccine has been lacking — especially for older Canadians.
"I've had patients who have showed up at the vaccination clinic expecting to get their second shot and have been turned away, so they are devastated emotionally, I've had people who have found out immediately beforehand," he said.
"I think their questions are very reasonable, which [are]: 'Do we have evidence to support this? Am I going to be at higher risk? How does this impact my behavior during the third wave now?'"
Stall, who is a member of NACI but does not speak on behalf of the committee, said it's important for public health officials to be transparent about the emerging data on delaying second doses and that the guidelines will likely change.
"I think we need to do a much better job of messaging," he said. "Because this population [of older seniors] has been living in terrible isolation for a year."
Dr. Lynora Saxinger, an infectious diseases physician and an associate professor at the University of Alberta, says updated guidelines will likely come in the near future as new data emerges.
She said it was important to note that the recommendations allowed for a maximum interval of up to four months, though the actual interval between doses could be shorter and the guidelines revised if new data showed certain groups were at higher risk.
"So the main thing is to kind of stay light on your feet and make changes that make sense to try to protect everyone the best we can," she said.
Saxinger said the second dose delay made sense given Canada's limited vaccine supply, because it allowed for an expanded vaccination rollout and offered protection to a greater number of vulnerable Canadians.
"It really will actually save a great many lives," she said.
"But if there's populations where deferring the second dose will actually make them less likely to be immune in the longer term, then obviously that's a place that has to be readdressed."
ABOUT THE AUTHOR
Adam Miller is a senior health writer with CBC News. He's covered health, politics and breaking news extensively in Canada, in addition to several years reporting on news and current affairs throughout Asia.
With files from Christine Birak and Marcy Cuttler
Credit belongs to : www.cbc.ca