Immediate vaccine improvement needed for Delta variant, says Moderna exec

• Moderna president said the delta variant is raising the bar for how good vaccines have to be.
• This comes as the U.S. compares booster shots.
• An FDA committee meets Friday to discuss boosters.

The president of the maker of a Covid-19 vaccine said the ultra-contagious delta variant has exposed weaknesses in vaccine protection and changed the outlook for ending the pandemic, according to a report.

Moderna president Stephen Hoge said on Wednesday that the delta variant has become “so good at infecting people and replicating that it raises the bar on how good vaccines have to be.”

“It’s actually shown some of the weaknesses that [vaccines] have earlier than you might expect,” Hoge told CNBC in an interview.

What you need to know about the Moderna vaccine

His comments came after Moderna released new data that showed the chances of breakthrough Covid cases in those fully vaccinated. Infections were less frequent in people who received their vaccine more recently, meaning that the vaccine’s protection begins to wane over time. Those results echo those of several other studies and are the reason booster shots are coming soon.

In the Moderna analysis, there were 88 breakthrough cases in a group of more than 11,000 people vaccinated between December and March, which is when vaccines became more accessible to the general public, compared with 162 cases from a clinical trial when participants were vaccinated between July and October 2020.

“The increased risk of breakthrough infections in … study participants who were vaccinated last year compared to more recently illustrates the impact of waning immunity and supports the need for a booster to maintain high levels of protection,” Stéphane Bancel, the Moderna CEO, said in a statement. 

Hoge said that the breakthrough cases aren’t necessarily all caused by the delta variant, but that the strain it is “weakening our defenses” during a crucial time — when vaccine protection is decreasing.

“It’s what has probably led to the … 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,” Hoge said.

The timing of the study comes just weeks after booster shots were authorized for all adults. Adults in the U.S. will be able to receive a third shot of the Pfizer or Moderna Covid-19 vaccines once eight months have elapsed since their second dose.

The plan was to have the shots ready by Sept. 20, but a few hiccups have occurred along the way. The Food and Drug Administration vaccine advisory committee is meeting today Friday to discuss whether third shots of the vaccines are safe and protective against infections.

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