In a bare 300-some words, Pfizer released a tantalizing figure describing a glimpse into the results of its phase 3 clinical trial for a coronavirus vaccine. The first batch of data suggests the vaccine is about 90% effective, the drug maker’s CEO Albert Bourla wrote, a rate far exceeding the expectations of even its own researchers.
“I’m very excited because we have been talking about a vaccine that might have a 50 or 60% efficacy. At least the early data suggests that the efficacy of this vaccine is much higher,” says Dr. Robert Finberg, a site investigator for the vaccine trial and a professor at the University of Massachusetts Medical School.
The announcement comes from an analysis on only a sliver of the data expected from Pfizer’s 44,000-participant clinical trial. The trial has not yet reached 164 confirmed COVID-19 cases among its participants, Finberg says, but more data will come soon. For now, this preliminary result has inspired a shared feeling among vaccine researches and health experts: hope.
“It absolutely gives me a sense of hope,” says Dr. Philip Landrigan, an epidemiologist at Boston College and director of the college’s global public health program. He was not involved with the vaccine research. “This news is very, very encouraging. We’ve all been waiting for a vaccine now since March, and I sincerely hope the findings are confirmed.”
The high efficacy rate may waver a bit as data from the rest of the trial continues to come in, Landrigan says, but he doesn’t expect it to fall too far. Assuming the success of the trial holds, the Food and Drug Administration approves the vaccine, and a large fraction of the population gets the injections, Landrigan says Pfizer’s vaccine will be a powerful weapon against the pandemic. Life a year or so from now, he says, may begin to move back towards “normal.”
“90% efficacy is very good and helpful as it gives a nice buffer against [people who refuse the] vaccine. We can still get to herd immunity even if we only vaccinate [approximately] 60% of the population,” Dr. Chris Gill, a vaccine researcher at Boston University who was not involved with the Pfizer vaccine, wrote to WBUR in an email. “I’m relieved.”
This early sign of success from Pfizer also bodes well for other vaccine developers, including Cambridge-based Moderna and a Beth Israel team working with drug giant Johnson & Johnson. All three of these vaccines use the coronavirus’s spike protein as a target and use the same underlying technology. If one of these vaccines appears to be working, then it’s extremely likely the others will, too, U. Mass Medical’s Finberg says.
“Those are rather similar vaccines. They’re all RNA vaccines and they’re based on the same protein. I’d say [the result’s are] very encouraging for the other vaccines,” Finberg says.
That’s critical to deploying vaccines as a public health tool, Finberg says. There are billions of people around the globe who need to be vaccinated, and any single drug manufacturer simply doesn’t have the capacity to churn out doses as quickly as the world would like, Finberg points out.
“We need more than one manufacturer. We need more than one vaccine. And I think we’ll have that. Other countries are obviously pursuing vaccines, too, and that’s a good thing. Hopefully those will be equally efficacious,” Finberg says.
And hopefully, Finberg adds, these vaccines will provide lasting protection as well. Pfizer does not yet have two months of data to show for the vaccine. He says it may be years until scientists know if any vaccine provides long-term immunity. The duration of the leading vaccines’ effects has been a source of anxiety for health experts who believe the frontrunners may have a design flaw that could cause immunity to wane within a year or months.
There's one more big caveat: Even if the Pfizer's vaccine meets the highest expectations, Finberg says it won’t be immediately available widely. It will take time to clear regulatory requirements and manufacture and distribute hundreds of millions of doses. People will still need to keep using
coronavirus tests, social distancing and face masks , Finberg says.
“I don’t know that this is necessarily the best vaccine,” Finberg says. “On the other hand, it gives one hope.”