Omicron and vaccines: Experts break down the science behind COVID-19 jabs
Global News
Experts say a third COVID-19 dose is needed to increase the level of antibodies following their decline. However, it's not clear how long an mRNA booster dose remains effective.
As researchers learn more about the Omicron variant of COVID-19, some say booster shots offer good protection against infection, but understanding how long the third dose remains effective is yet to be seen.
According to Jesse Papenburg, a pediatric infectious disease specialist and medical microbiologist in Québec, the third COVID-19 booster dose has proven effective against Omicron, particularly against hospitalizations.
But the science behind how much protection Canadians are getting with two doses versus three is a “little complex,” said Papenburg.
“Two doses offer some decent protection initially, but that protection drops off pretty dramatically and probably after three months it is pretty close to nothing … and that’s because the Omicron spike protein is different enough that it’s able to partially evade the antibodies that we produce,” said Papenburg in a Zoom interview with Global News.
Papenburg explained that the third dose helps increase people’s antibody levels in fighting infections as they start to decline.
“You see that phenomenon: soon after your first dose, we have pretty good protection against any infection, but how long will that take to wane is yet to be seen because we don’t have as many studies to look at a long-term period against Omicron infection and certainly not in Canada after the third dose,” said Papenburg.
Papenburg said data from a study done in the United Kingdom has shown a third dose of COVID vaccine has 88 per cent effectiveness against hospitalization.
An ongoing study out of Ontario first published on Jan. 1, 2022, found that seven days after a booster shot, mRNA vaccines were 93 per cent effective at protecting against the Delta variant. That number fell to 60 per cent against Omicron.
