The fast-spreading delta variant is so contagious, it’s exposed weaknesses in vaccine protection and changed the outlook for ending the pandemic, Moderna President Stephen Hoge said late Wednesday.
Delta is “just so good at infecting people and replicating that it raises the bar on how good vaccines have to be,” he said in a phone interview. “It’s actually shown some of the weaknesses that [vaccines] have earlier than you might expect.”
Moderna shared Wednesday a new analysis from its phase three study that showed the incidence of breakthrough Covid cases, which occur in fully vaccinated people, was less frequent in a group of trial participants who were recently inoculated, suggesting the Covid vaccine’s protection wanes over time.
There were 88 identified breakthrough cases out of 11,431 people vaccinated between December and March, the company said in a press release, compared with 162 breakthrough cases out of 14,746 trial participants vaccinated in July through October of last year.
The breakthrough cases are not all delta’s fault, Hoge said. He said he suspects the Covid cases in vaccinated people are a result of both vaccine protection waning over time and the highly transmissible variant.
“The delta variant is not an immune escape variant,” he said, adding the variant is simply “weakening our defenses” at a time when vaccine protection is declining.
“It’s what has probably led to the phase three results that we’re seeing right now, it’s led to the difference in the real world efficacy that’s been reported between the vaccines this summer,” he said.
Hoge said the drugmaker’s latest results, which haven’t been peer-reviewed yet, builds its case for the wide use of Covid booster shots.
“It’s the reason to get ahead of the problem and boost,” he said.
His comments come ahead of a Food and Drug Administration vaccine advisory committee meeting Friday when a group of outside experts will discuss whether there is enough data to support widely distributing booster shots across the U.S.
The group, called the agency’s Vaccines and Related Biological Products Advisory Committee, will debate administering third doses of Pfizer and BioNTech‘s vaccine as federal health regulators say they need more time to review Moderna’s application for extra doses.
How the meeting goes could have consequences for Moderna’s booster shot plans going forward.
The scientific community is currently split on the need for booster shots for the general public.
The Biden administration has said it wants to begin offering booster shots to the general public as early as next week, pending authorization from the FDA. The move is part of President Joe Biden‘s broader plan to confront a higher number of Covid cases fueled by the fast-spreading delta variant.