The data from Israel on the effectiveness of – and of course, the eventual need for – a 3rd dose of vaccine is getting pretty compelling.
According to a report from the Ministry of Health in Israel, a third dose of the Pfizer COVID-19 vaccine has given four times greater protection against COVID-19 infection and has been 5-6 times more effective in preventing serious illness and hospitalization in seniors than just two doses have been.
This certainly doesn’t yet mean that everyone in Canada should immediately line up for a 3rd vaccine dose.
That’s in large part because the dosing schedule that was used in Israel was a very strict 2 doses over 3 weeks max, while in Canada, the 2nd dose was administered after many more weeks than the bare minimum of three, as long as 12 weeks after the 1st dose for some Canadians, and there is very good evidence that delaying the 2nd dose not only allows for a better antibody response than the one used in Israel (and that was strongly recommended by Pfizer) but it also likely means that the immune response won’t tail off even in higher-risk Canadians nearly as quickly as it did in Israeli seniors.
But it does point out that the immune response from these vaccines is not forever and sooner or later, it is very likely that at the very least, those people who have impaired immunity will require some kind of booster to fight off the new and newer variants.
But despite Delta, it doesn’t seem like that time has yet arrived.