Volunteers still needed to test several vaccines
Two COVID-19 vaccines might be nearing the finish line, but scientists caution it’s critical that enough people volunteer to help finish studying other candidates in theU.S. and around theworld.
Moderna Inc. and Pfizer Inc. recently announced preliminary results showing their vaccines appear more than 90% effective, at least for short-term protection against COVID-19.
If those early results hold upandU.S. regulators agree the shots are safe, emergency use of small, rationed supplies could start in late December. Other countries with contracts for early doses would undertake their own reviews.
Pfizer said Wednesday that new test results show its coronavirus vaccine is 95% effective, is safe and also protects older people most at risk of dying — the last data needed to seek emergency use of limited shot supplies.
Theannouncementfrom Pfizer and its German partner BioNTech comes as the team is preparing within days to formally ask U.S. regulators to allow emergency use of the vaccine. Anticipating that, a Food and Drug Administration advisory panel is on standby to publicly debate the data during the second week of December.
The companies also have begun “rolling submissions” for the vaccine with regulators in Europe, the U.K. and Canada and soon will add this new data.
But multiple vaccines will be needed to meet global demand and help end the pandemic, raising concern that studies that still need to sign up thousands of volunteers could run short if people wait for an already OK’d option instead.
“We don’t want to see that happen,” said Dr. JamesCutrell, aninfectious disease expert atUTSouthwestern Medical Center in
Dallas.
Supplies aside, other COVID-19 vaccines under developmentmaywork differently in different populations, and “we likely will benefit fromhaving amenu of vaccine options,” Cutrell said.
“We still need volunteers,” stressedNational Institutes of Health Director Francis Collins, urging Americans to sign up.
Additionally, participants in the Moderna and Pfizer studies who originally got placebos would almost certainly be offered the real vaccine if the U.S. Food and Drug Administration allows emergency use. But no one knows how long protection would last, meaning those studies also must continue to track recipients somehow.
“It’s one thing to be effective two months after your last vaccination and another thing to be effective a year” later, said Dr. Jesse Goodman of Georgetown University, a former
director of the FDA’s vaccine division. “It’s going to be really important to complete these clinical trials and the trials of the other vaccines so we can make comparisons.”
The promising Moderna and Pfizer news bodes well for some of their competitors, said Dr. Anthony Fauci, the U.S. government’s top infectious disease expert whose team at NIH helped develop the Moderna candidate.
Those shots target the “spike” protein that studs the surface of the coronavirus, and the early results prove that’s enough to generate “a protective response,” Fauci said. “Conceptually, this looks good” for other spike-focused vaccines made in differentways.
Here’s a scorecard of the front-runners in the global vaccine race:
vaccines: TheModerna-NIH vaccine and the candidate developed
Genetic code
by Pfizer and its German partner BioNTech aren’t made with the coronavirus itself, meaning there’s no chance anyone could catch it from the shots.
The vaccines are made with a brand-new technology that injects a piece of genetic code for the spike protein. That messenger RNA, or mRNA, instructs the body to make some harmless spike protein, enough to prime the immune system to react if it later encounters the real virus.
There are no licensed mRNA vaccines for people, so scientists had no idea if or how well the COVID-19 candidates mightwork.
Both manufacturers are working to scale up production in factories in the U.S. and Europe. They can’t simply partner with other vaccine companies to take on some of the work because the technology is so different than theway most of today’s shots aremade.
“It is not a very easy or quick swap,” said Moderna CEO Stephane Bancel.
A different way to target the spike protein: Use another, harmless virus to carry the spike gene into the body. Once again, the body produces some spike protein and primes the immune system.
Britain’s Oxford University and AstraZeneca are making their version of this “viral vector” vaccine with a cold virus, or adenovirus, that normally infects chimpanzees. Studies of tens of thousands of people are underway in the U.K., U.S. and several other countries.
Johnson & Johnson is using a human adenovirus for its version, and is the only option in advanced U.S. testing aiming to show if a single dose rather than twowould be enough.
China’s government authorized emergency use of CanSino Biologics’ adenovirus shots in the military ahead of any final testing. Russia likewise began offering an adenovirus vaccine ahead of late-stage tests.
Trojan horse vaccines:
Protein vaccines: Novavax makes its vaccine candidate by growing harmless copies of the coronavirus spike protein in the laboratory and packaging them into virus-sized nanoparticles.
There are protein-based vaccines against other diseases, so it’s not as novel a technology as some of its competitors. Novavax has begun a large final-stage study in Britain, and is set soon to begin another inthe United States.