Hopes that a COVID-19 vaccine is imminent were further buoyed on Monday by news from U.S. drugmaker Moderna that early data shows its vaccine to be nearly 95 percent effective in preventing the coronavirus. The news comes one week after Pfizer and BioNTech SEannouncedthat their vaccine was 90 percent effective in phase III clinical trials.
Experts say the announcement not only portends good news from the 10 remaining frontrunners in the race for a vaccine but also suggests that COVID-19 itself may be more easily “vaccinatable” than previously thought.
The results of Moderna’s vaccine were released by the National Institutes of Health’s Data Safety Monitoring Board (DSMB), an independent body of experts who vet research for safety and efficacy. The company’s phase III trial involved more than 30,000 individuals from the U.S. and was performed in partnership with the National Institute of Allergy and Infectious Diseases (NIAID).
President Trump, whose administrationreached an agreementto manufacture 100 million doses of the vaccine in August, urged historians in atweetto note that the approval took place “under my watch.” In astatement, Moderna’s chief executive officer, Stéphane Bancel, confirmed the promising nature of the results. “This positive interim analysis from our Phase 3 study has given us the first clinical validation that our vaccine can prevent COVID-19 disease, including severe disease,” he said in the press release.
Top epidemiologists and other experts also praised the news on Twitter. “Another great result! Starting Monday morning with happy news,”tweetedDr. Akiko Iwasaki, a renowned immunologist at the Yale School of Medicine. “Very exciting to see 94% efficacy,”wroteDr. Eric Topol, professor of molecular medicine at the Scripps Research Institute (TSRI), adding, “this replication of Pfizer’s high efficacy tells us the virus is eminently vaccinatable.”
So what does “vaccinatable” actually mean — and why might COVID-19 fall under that category?
While it will likely be months before there is a clear answer to that question, experts have some theories. “It suggests that perhaps it is easy to develop vaccines against this disease and that we can elicit or create very strong immune responses that protect people,” says Dr. Richard Kennedy, an immunologist and co-director of the Mayo Clinic’s Vaccine Research Group.
Kennedy says that it could simply be that SARS-CoV-2 is an easier virus to prevent. “It depends on the pathogen. Some of the viruses like HIV, for example, we’ve been working on that for decades, and that’s a far more complicated problem than coronavirus,” Kennedy tells Yahoo Life. “There are other vaccines that it’s taken 10 or 20 years and we’re still working on effective vaccines.”
He clarifies that this doesn’t mean COVID-19 is a simplervirus— the way it sickens individuals, in some ways, still eludes doctors — it could simply suggest that it’s easier to prevent. The efficacy of other vaccines, he says, bolsters this point. “Many vaccines that we’ve got now are anywhere from 30 to 50 or maybe 60 percent effective. Now compare that with two vaccines that have over 90 efficacy,” he says. “It’s very promising that hopefully the other vaccine types that are moving their way through the clinical trial process will also have very high efficacy rates.”
Although it may be that the virus is “eminently vaccinatable,” Kennedy says there’s also a chance that the novel technology being used, called messenger RNA, may play a role. mRNA, a pioneering approach, uses SARS-CoV-2’s genetic code to target the spike protein on the surface of the virus. This allows the body’s immune surveillance cells, as Dr. Gregory Poland, who co-directs the Mayo Clinic’s Vaccine Research Group,told Yahoo Life earlier, to “recognize it as a foreign and mount an immune response against it.”
Whether it’s the messenger RNA or the fact that SARS-CoV-2 is easier to prevent will be a question that remains unanswered until results on the vaccine candidates that use alternate methods — such as aninactivated virus— are released. And Kennedy adds an important caveat: These phase III trials likely show the “optimal” result for efficacy, meaning when the vaccine is released to more vulnerable populations, the efficacy rate may decrease.
Still, he says there is reason for hope. “We’ve been testing mRNA vaccines in a variety of scenarios, but this is the first time they’ve ever gone this far into clinical trials, and so in that regard, we’re breaking new ground,” he says. “This is the first time we're seeing them in action and able to get a sense of ‘are these really going to work?’ And in that regard, it’s very promising news from both of these two vaccines.”