Should you get your 4th COVID-19 vaccine dose now? Alberta experts weigh in

Deciding whether or not to roll up your sleeve for a fourth dose of the COVID-19 vaccine now or wait for new vaccines later on will be a calculation of risk for many Albertans, according to some doctors and scientists. Others, though, are urging people to get that shot right away.

Starting July 20, everyone 18 and over is eligible for a second booster as long as they wait five months after their last dose.

The change, announced Tuesday by the provincial government, comes when COVID transmission is rising in Alberta and the more transmissible BA.5 subvariant has taken over.

"With the combination of waning immunity and increased viral transmission, now is the right time for a number of people to consider getting that extra booster shot to make sure their immunity is as high as possible," said Craig Jenne, associate professor of microbiology, immunology and infectious diseases at the University of Calgary.

According to Jenne, that includes both people who are at high risk due to underlying health conditions and those who may be involved in higher risk activities such as travel.

"We are seeing a lot of infection associated with travel. There are a number of viral hot spots around the world. And for people that might be going somewhere on a vacation where there's a higher risk of exposure, they may want to ensure their immunity is topped up before they go." 

Anyone who is unsure, he said, should have a discussion with their health-care provider.

'We're in a difficult spot'

For otherwise healthy people, the decision may not be quite as clear cut, some experts argue.

With new bivalent vaccines in the works, which are designed to target earlier versions of Omicron, a layer of complexity is added to the equation.

"We're in a difficult spot," said Dr. Stephanie Smith, an infectious disease specialist at the University of Alberta Hospital, acknowledging there are a large number of people who've had third doses more than six months ago and have waning immunity.

"Should we wait for the bivalent vaccine versus take the fourth dose now? And if we take the fourth dose now, will that make us ineligible for the bivalent vaccine if it does become available in the fall?"

• What a 4th COVID shot can do for you — and what it can't

CBC News asked Alberta Health for some clarity around how long Albertans might have to wait after a fourth shot to be eligible for a bivalent vaccine should one be approved. The province did not answer that specific question. Instead, it reiterated its guidance on wait times for fourth doses.

There are many uncertainties, according to Smith, including whether or not Health Canada will approve a bivalent vaccine, when that could happen and if there would be enough supply available in time for a fall or winter surge.

"There's a lot of different issues at play and a lot of challenges in terms of being able to navigate what the right decision is.… At the end of the day, it really comes down to risk of severe disease."

Smith said Albertans who are high risk and are within the window of eligibility should book their second booster right away.

And she hopes there will be more clarity from Health Canada in the next three to four weeks on the future of bivalent vaccines so people can make a more informed decision about the timing of their fourth dose.

"Although the current vaccine is not particularly effective in preventing disease … it certainly will give protection against severe disease."

In a tweet on Tuesday, Dr. Raj Bhardwaj advised against waiting.

"[An] 'Omicron specific' booster likely won't be available in quantity until Nov-Dec, so getting a booster now likely won't delay your eligibility for that one," said the Calgary urgent care doctor and family physician.

"Cases are rising fast now: address the current risk. As we've seen, few people can reliably tell the future in this pandemic."

With BA.5 surging, Dr. Noel Gibney agrees now is the time for all eligible Albertans to get their second booster.

"The challenge we face is that it's probable that a lot of people are going be infected, and even though … [BA.5] tends not to cause as much severe disease, by virtue of so many people being infected, we potentially risk a huge strain on our hospitals. And that's been seen in Europe," said Gibney, a professor emeritus in the department of critical care medicine at the University of Alberta.

"We very definitely risk having a very significant seventh wave … and so there's no question in my mind the timing of this is really quite good."

Gibney doesn't think people should wait for a potential new vaccine in the fall. And he's urging anyone who hasn't yet had a third dose to do that, too.

"I would be surprised if [a bivalent vaccine] is generally available in Canada before December. And so that's going to be quite late given that by then we'll have a BA.5 and probably, I suspect, something else will happen three months after that. So December would be the time I would suspect we'll see another wave," he said.

"If you haven't [had BA.5 recently], it doesn't make sense to wait when there is a vaccine available that can reduce your possibility of becoming seriously ill with this new variant."