Eight week interval now recommended to protect against Delta variant

·3 min read

Despite strong encouragement from many for the province to reduce the wait time for AstraZeneca, the province said it would be sticking to a 12-week interval between shots. However, over the weekend, the plans changed. The province further accelerated the second dose to those who received their first dose of an AstraZeneca COVID-19 vaccine to eight weeks, with informed consent.

With informed consent, individuals can choose between a second dose of AstraZeneca or an mRNA vaccine, at an eight to 12-week interval, recognizing that while waiting 12 weeks helps to ultimately provide more protection, some may choose to receive their second dose sooner to have the increased protection provided by a second dose earlier. All of these options provide protection against COVID-19, including the Delta variant, and have been deemed safe.

According to Dr. David Colby, Chatham-Kent’s Medical officer of Health, three factors come into play to make this happen.

“One is supply. That’s been a constant issue. Since the get-go, we still don’t have all the vaccines we would like to have for our vaccination campaigns,” said Colby.

The region’s top doctor also said there are issues with getting enough AstraZeneca for those who want to complete their AstraZeneca series.

“There shouldn’t be a problem getting those people boosted in multiple locations,” said Colby. “We have pop-up clinics, and we have pharmacies that have vaccines, of course, the mass vaccination Center at Bradley.”

Colby said the third factor is the fact that there is currently a race between getting the second dose in arms to protect against the incoming Delta strain. He added there is increasing evidence that 12 weeks appears to be the sweet spot for optimum performance of the vaccine.

“So we’ve got the best way to give it at 12 weeks, but we want to hurry up and give that second dose, so everybody is protected. And trying to balance that with the ongoing issues of supply is what we spend all our day doing,” added Colby.

Many infectious disease experts agree that the two doses required to be fully vaccinated against coronavirus will offer stronger protection against the delta variant of the virus, which has become the dominant strain in the U.K. and is now gaining momentum in Canada.

According to new modelling released last week, the Delta variant will likely be the dominant form of the virus by summer. The modelling found a second vaccine dose is more than twice as effective against the Delta variant than a single shot.

“It’s really important to make sure that, as much as possible, we accelerate second doses,” said Adalsteinn (Steini) Brown, the head of University of Toronto’s School of Public Health and the co-chair of the science table.

According to the numbers, Ontario has sped up second shots for adults 70 and over, as well as those who received first doses on or before April 18. As of June 11, 73 percent of adults in Ontario have received a first dose, while 11 percent are fully immunized.

The changes to Ontario’s vaccine program come as the province enters the first step of its reopening plan. Elliott said it’s too soon to say whether the province will be able to move to the next step of reopening more quickly than previously announced.

Bird Bouchard, Local Journalism Initiative Reporter, The Ridgetown Independent News

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