Source: Asbury Park Press
A candidate vaccine against COVID-19 developed by the federal government and Moderna, Inc., appears to be safe and to trigger an immune response, according to data from an early phase trial. But whether that immune response is enough to protect someone from the coronavirus that causes COVID-19 remains unclear, according to several experts who reviewed the results.
Moderna’s chief medical officer Dr. Tal Zaks said although the protective effect of their vaccine can’t technically be known yet, all indications are that mRNA-1273 will be both safe and effective.
Zaks said the levels of protective antibodies produced by the trial participants were similar to those found in patients who had recovered from COVID-19, suggesting that the candidate vaccine provides the same protection as an infection. Additionally, the mRNA-1273 candidate did not generate a kind of immune cell that with other diseases has made vaccinated people worse off, Zaks said.
The clinical trial was led by Dr. Anthony Fauci’s Vaccine Research Center at the National Institutes of Health. Just two months after Chinese scientists revealed the virus’s genetic sequence, a volunteer in Seattle was injected. That set a record for getting a new candidate vaccine into human trials.
“It looks like their vaccine was able to induce virus neutralizing antibody, which is positive,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston. “But it’s hard to know if the level of virus neutralizing antibody will be sufficient to induce protective immunity, or if it compares favorably with other (vaccine) candidates.”
“These are good results,” agrees Dr. Nadine Rouphael, who helped lead the trial at Emory University School of Medicine. Neutralizing antibodies are key for fighting other infections, she added, but there are a lot of questions about COVID-19. “How long (the antibodies) will they stay, (and) what is the right level of protection remains to be determined.”
Also, learning whether the vaccine is protective will require a much larger study. A so-called Phase 3 trial with 30,000 participants is slated to begin on July 27, Zak confirmed. Thousands of people volunteered for the small Phase 1 trial, Rouphael said, adding that she hopes people will continue to sign up for the research.
The goal is to have a vaccine ready in limited batches by January, or at the latest next summer. There is no way to tell whether either of those timetables are feasible. Historically, vaccines take many years to develop.