By
Andrew Russell ,
Carolyn Jarvis & Emanuela Campanella
Global News
Published October 2, 2021
5 min read
Moderna’s president is warning that Canada could see a rise in so-called “breakthrough” infections of COVID-19 among fully vaccinated people by Christmas time, prompting the need for a booster shot for the broader public.
“In December and January, when flu season comes back and when respiratory viruses really take off around the holidays, it could become a very bad moment because you’ll see high forces of infection and breakthroughs,” president Stephen Hoge said in an exclusive interview with Global News’ current affairs show The New Reality.
Moderna has been studying the immune response to its vaccine since the summer of 2020, when 30,000 participants received two doses, 28 days apart. Moderna says data from that trial shows antibodies start to wane about six months after the second shot.
WATCH: Antibodies only half the story of immune protection: experts
While antibodies are expected to decrease over time, Hoge said alarm bells started going off over the summer as outbreaks fuelled by the Delta variant surged worldwide. Moderna researchers began to see a spike in breakthrough cases of symptomatic COVID-19, among those fully vaccinated clinical trial participants.
This is prompting Moderna to call for a booster for fully vaccinated adults.
“None of us want to be in a situation where we’re showing up six months or three months late … where we’re seeing breakthrough infections, severe disease, hospitalization, and even death.”
Canadian data shows vaccine effectiveness is still remarkably robust at preventing severe outcomes, like hospitalization, from COVID-19. Hoge said that could be, in part, because some Canadian provinces delayed the interval between the first and second doses by up to four months, prolonging immunity.
The decision to stretch the interval between doses was a controversial move as health officials weighed the benefits of getting people fully vaccinated versus giving more people partial immunity with one dose.
“In retrospect, we will probably say that time between the doses extended the durability,” Hoge said.
“The more recently you were boosted with your second dose, the less likely you’re going to need a third dose booster. And that’s good news,” he said. “The challenge for all of us is you also don’t want to wait too long.”
WATCH: Boosters could be needed annually says Moderna’s president
But fast-forward six months from summer – after many Canadians received their second doses – and the number of breakthrough infections could change, Moderna’s internal trial data suggests.
“Do we expect there to be waning immunity in populations like Canada that had separated booster doses? I think the answer is yes,” Hoge said.
“That’s the concern, that by Christmas things could look very different.”
The concerning forecast comes as health officials in the U.S. are launching campaigns to provide booster shots for millions of vulnerable people who received the Pfizer-BioNTech vaccine. The Centres for Disease Control (CDC) formally approved plans for additional shots for people who work in high-risk jobs like teachers and health care workers, as well as anyone over 65.
Canada’s National Advisory Committee on Immunization (NACI), meanwhile, has only recommended additional shots for people with compromised immune systems and those living in congregate care settings, like long-term care homes.
The booster debate has divided the international scientific community, with some saying there is no current need for additional doses for healthy adults, while others say there is mounting evidence showing immunity is declining.
Studies from Pfizer and the CDC have also suggested evidence of waning vaccine effectiveness.
One CDC study evaluated data from New York State from May 3 to July 25, when the Delta variant represented more than 80 per cent of new cases. The effectiveness of vaccines in preventing infection in adults declined from 91.7 percent to 79.8 percent during that time, the study found.
During those weeks, New York recorded 9,675 breakthrough infections and 1,271 hospitalizations in vaccinated people, roughly 15 per cent of all COVID-19 hospitalizations.
However, a series of contrasting studies released by the CDC have shown the vaccines are working well at preventing severe disease.
A pair of analyses released last month showed that vaccines are still holding up in the fight against COVID-19. One study indicated unvaccinated people were about 4.5 times more likely to become infected, and were more than 10 times more likely to need hospitalization or die from COVID-19 than people who are fully vaccinated.
Canadian public health officials, meanwhile, say they are evaluating data from other countries before making any further recommendations on booster doses.
“(NACI) continues to review evidence on the effectiveness of COVID-19 vaccines in key populations and the general population, including the duration of protection that will inform decisions regarding booster doses,” a spokesperson with the Public Health Agency of Canada said in an email.
Moderna has asked regulators in the U.S. to greenlight a half-dose (50mcg) of its original vaccine for use six months after the second shot. Hoge says its data shows the booster brings antibody levels even higher than after the initial shots across all age groups.
They have yet to make a formal submission to Health Canada for approval but are planning to do so imminently, Hoge said.
“Our clinical trials – which are the longest exposures to the vaccine and the virus that we have – are starting to suggest to us that it’s time to get concerned and get ready,” he said.
“We’ll present that data to Health Canada and to recommending bodies globally, but they then need to decide ‘OK, does that cause them to take action for their people?’”
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