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Moderna co-founder says COVID-19 booster shots will 'almost certainly' be needed


The co-founder of Moderna says a regular booster shot will ‘almost certainly’ be needed to increase protection against COVID-19.

Canadian stem cell biologist Derrick Rossi told CTV News Channel on Wednesday that the body’s immune system is "primed by vaccination or primary infection," however that immunity wanes over time if those systems are not challenged.

"I think boosters are most likely going to be in the cards and evidence is pointing towards that so this is the evidence emerging out of Israel that a booster is almost certainly the way," Rossi said.

The comments come after an analysis done in Israel showed that Pfizer-BioNTech's coronavirus vaccine appeared to be less effective against infections caused by the Delta variant compared to other strains of COVID-19.

In a statement issued Monday, the Israeli government said the mRNA vaccine provided 64 per cent protection against COVID-19 infection. In May, when the Delta strain had not yet spread widely in the country, it found that the Pfizer shot was roughly 95 per cent effective against all infections.

The Israeli government did not release underlying data or other details about its analysis and Pfizer said it could not comment on unpublished data.

In a lab study, Moderna says its mRNA vaccine showed to work against the Delta variant first identified in India with a modest decrease in response compared to the original strain.

Rossi said variants are inevitable with a pandemic of this scale.

"With an endemic virus, it might not be surprising that we need a booster shot every year," Rossi said. "Immune systems do what they do, they're great at it in the short term, but immunity does diminish with time, and especially with the emergence of more transmissible and potentially more deadly variants."

However, Rossi said he believes the booster shots will be "variant specific." Rossi explained that mRNA technology can tailor a vaccine to a specific pathogen.

The technology uses messenger ribonucleic acid (mRNA), which is a molecule that provides cells with genetic instructions for making proteins that are needed for numerous cellular functions in the body, including for energy and immune defence.

In a lab, scientists develop synthetic mRNA that is able to instruct the body’s cells to develop that same distinctive spike protein from SARS-CoV-2, the virus that causes COVID-19. After the piece of protein is made, the cell breaks down the genetic instructions and gets rid of them.

The immune system then identifies the foreign spike proteins produced by the cells and initiates an immune response by building antibodies against them.

Moderna began developing a booster shot in February and announced in May that early human trials showed that a third dose of either its current COVID-19 vaccine or an experimental, variant-specific shot increased immunity against the Beta and Gamma variants, first found in South Africa and Brazil, respectively.

The company said the booster shots also increased antibodies against the original version of COVID-19.

"It's for sure going to be variant specific boosters which will of course be great for variants," Rossi said. "New [variants] will emerge but again, the technology like this will be able to really pivot quickly to address it I think."

While Rossi is hopeful that regular booster shots will help to end the COVID-19 pandemic, he said it will only work if everyone continues to roll up their sleeves.

"We need to get our vaccines, and we probably in all likelihood need to get our boosters," Rossi said

With files from's Jackie Dunham Top Stories

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