Local expert answers questions about third doses, vaccine for kids

During Waterloo Region's most recent community update, Dr. Kelly Grindrod of the University of Waterloo, School of Pharmacy, helped clear up some lingering questions regarding third doses of the COVID-19 vaccine.

“This isn't necessarily a surprise,” Grindrod said in regards to third doses. Three dose vaccines aren't uncommon. Hepatitis is an example of one that many of us already have.

“This is a data driven decision,” added Grindrod. “At the beginning of the vaccine campaign, people were saying 'I'm waiting for long-term data' … well this is long-term data. This is exactly what we're looking for … we want to know how long the vaccines work.”

Researchers are now in the long-term, follow-up phase, and Grindrod said more than anything, it's about efficacy and how long are we protected from two doses, and furthermore, a third dose.  She added, as more long-term data becomes available, it will determine if more booster shots are needed – five years, 10 years, annually, or perhaps non at all.

“We're looking specifically at breakthrough infections,” said Grindrod. “We do know there are certain populations more at risk, so we're seeing recommendations for those groups to have their third dose now.”

Further recommendation on third doses will come from the National Advisory Committee on Immunization (NACI) and the province.

For those asking about mixing vaccines between Pfizer and Moderna, Grindrod said they're still generally being treated as interchangable. “For your third dose, you would get the same as your second. We think of Pfizer and Moderna as pretty much the same vaccine.”

Meanwhile, vaccines for children aged 5 to 11 are still being reviewed by Health Canada.

“The United States have given around a million doses,” added Grindrod. “We've seen a lot of the data, and we followed the United States approval process.”

NACI will also provide recommendations on how to vaccinate kids, such a the time in between doses.

“They're going to tell us if it's 21 days apart, eight weeks apart, or longer.” Grindrod added.

Kids will receive a lower dosage than adults.  Grindrod said she hopes, if all goes well, vaccines for children will be approved by the end of November.