Albertans who jumped on fourth COVID doses this summer must wait for bivalent booster

Alberta's rollout of the bivalent COVID vaccine has some people wondering if they made the right choice getting their fourth dose after the province expanded eligibility over the summer.  

But experts say don't second guess yourself.

The new bivalent booster, which targets the original virus and the Omicron BA.1 strain, was approved by Health Canada on Sept. 1.

Alberta Health announced this week it will start offering the booster to everyone 18 and over starting Sept. 21.

"The data would suggest there is an increased antibody response against BA.1 as well as BA.4 [and] BA.5 with this bivalent vaccine compared to previous vaccines," said Dr. Stephanie Smith, an infectious disease specialist at the University of Alberta.

But at least some of the 442,524 Albertans 18 and over who have already rolled up their sleeves for the fourth shot of the original vaccine are wondering what it means for them.

Five-month window still applies

Fourth dose eligibility was expanded to include all adults 18 and up in late July.  Before that it was available to select groups including seniors over 70.

At the time many people struggled to decide whether to get a fourth dose then or hold out for the more targeted bivalent version. It was a calculation of risk.

"For those that have received their fourth dose recently, I think that it is a bit challenging," Smith said.

The trouble is, while the bivalent is open to people with any number of boosters, the province recommends waiting at least five months after your last dose or COVID infection to get the bivalent shot.

Those who opted to get their fourth dose after this summer's announcement have a long wait ahead. And COVID-19 numbers are expected to rise as the weather cools and people move indoors.

"Now some people will feel maybe they're not as well protected and so should they be getting it sooner? But I think the data's really not there to suggest that they should be getting the bivalent vaccine within a couple of months of their fourth dose," Smith said.

 "They should be reassured they do have some protection ... they'll just have to delay their [bivalent] booster dose until potentially the new year or later in the fall season."

'They shouldn't regret that'

University of Alberta infectious disease specialist, Dr. Lynora Saxinger, agrees.

"You make the decision at the time with what you know. And I think there still was COVID transmitting a lot over the summer and some of those people, had they not had the shot, might have gotten it over the summer. Now they're second guessing," she said during an interview on CBC Radio's The Homestretch.

"At the end of the day, all of the data shows that the third and fourth dose [of the original vaccine] offer additional benefit. They basically will halve your risk of severe outcomes. ... So I think they shouldn't regret that." 

Saxinger said work will be done in the months ahead to analyze the optimal timing for the bivalent shot after a fourth dose of the original vaccine.

Meanwhile, Smith hopes the release of the new bivalent vaccine will prove more appealing to Albertans who have, so far, resisted a booster dose. 

"I'm hopeful that it will actually encourage more people to get their booster because they see it as something different as opposed to just another dose of the same old vaccine."