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.

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?"

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."