Here's what you need to know about 4th doses of COVID vaccine
CBC
If you've heard that Israel is well underway administering fourth doses of COVID-19 vaccine, you may be wondering if it will soon be time to hunt for another vaccine appointment yourself.
It's long been the plan to offer immunocompromised Canadians a three-dose primary series of shots followed by a booster, but it's not clear yet that a fourth round of vaccine is necessary for the broader population.
Israel's situation is a little different, explains virologist Darryl Falzarano, a research scientist at the University of Saskatchewan in Saskatoon, who studies virus transmission as well as immune response to infection.
"Israel's vaccine campaign started earlier, so they're longer out from their third dose than a lot of other places, so they're in a slightly different position," said Falzarano, who is also a deputy with the Coronavirus Variants Rapid Response Network (CoVaRR-Net), a group of researchers that advises the federal government on how to respond to SARS-CoV-2 variants.
Israel started administering boosters in late July, which means immunity from that booster is more likely to be waning there just as the Omicron variant has sent cases skyrocketing around the globe.
Israel is now offering fourth doses to everyone over 60, immunocompromised people and health-care workers. Its health ministry said Friday it had administered more than 500,000 fourth doses.
It's too soon to say, but Israel has been right about boosters before.
"I think they were right on the third dose potentially really being necessary and useful at that five- or six-month mark," said Falzarano, who holds a PhD from the Department of Medical Microbiology at the University of Manitoba. "But we're really going to have to wait to see ... whether a fourth dose is really needed and whether a fourth dose is going to help."
Only once enough time has passed — likely at least a few months — will researchers know whether people who received fourth doses had more protection against infection, severe illness and hospitalizations than those with three.
Dr. Isaac Bogoch, an infectious diseases specialist based out of the Toronto General Hospital, called that "the million-dollar question."
While there are only "small shreds" of data about the efficacy of fourth doses available, the theory is that certain groups might benefit from a fourth dose, Bogoch told Dr. Brian Goldman, host of CBC podcast The Dose — for example, the immunocompromised and the elderly.
"It looks like all arrows are pointing in the direction, even in Omicron, that three doses is better than two," said Bogoch, who is also a member of Ontario's COVID-19 task force.
"The question here is what is the meaningful short-term, medium-term and long-term protection that a fourth dose affords [a person], versus three doses?"
Falzarano said researchers will be studying people's antibody levels in the months following a third dose. It's expected that antibody level jumps after a vaccine, then slowly wanes in the months to follow. But the picture four to six months down the road is key, he said.
P.E.I.'s Public Schools Branch is looking for 50 substitute bus drivers, and it'll be recruiting at three job fairs on Saturday, June 8. The job fairs are located at the Atlantic Superstore in Montague, Royalty Crossing in Charlottetown, and the bus parking lot of Three Oaks Senior High in Summerside. All three run from 9 a.m. until noon. Dave Gillis, the director of transportation and risk management for the Public Schools Branch, said the number of substitute drivers they're hiring isn't unusual. "We are always looking for more. Our drivers tend to have an older demographic," he said.