4th COVID-19 dose: What is the value of an additional booster?
Global News
A fourth COVID-19 vaccine dose can increase antibody levels and improve protection against infection, severe outcomes, according to experts and research.
As a seventh wave of COVID-19 takes shape in parts of the country, more Canadians are now being offered a fourth vaccine dose.
In Ontario, starting Thursday, anyone aged 18 and older who had their first booster at least five months ago can now book another one.
Other provinces and territories, like Quebec, Prince Edward Island, Nunavut and Yukon, have also opened up their eligibility for second boosters — which would be a fourth dose of the vaccine — to anyone over the ages of 18 and 12, respectively, who have waited a certain number of months since their last dose.
With questions and mixed messaging around the timing of an additional booster, many are wondering if they should get vaccinated now or wait for the fall when Pfizer and Moderna are expected to roll out updated bivalent vaccines designed to protect against both the original strain and Omicron variant of the virus.
Tania Watts, an immunologist and professor at the University of Toronto, said because we are vulnerable to the current wave now, there is no reason to delay.
“Giving that extra fourth dose, it’ll bring up the antibodies again for a while and then they’ll taper off,” she said.
“The protection against severe disease in healthy people stays more constant, but there is a transient increase in protection against infection if you get that fourth dose.”
The current booster shots that are being offered have exactly the same formula as the first three doses, based on the original Wuhan strain of COVID-19.