An experimental coronavirus vaccine developed by Moderna Therapeutics in association with the National Institutes of Health (NIH) has been found safe and effective at inducing immune responses in all of the participants in the Phase 1 trial.
These results, published Tuesday in the New England Journal of Medicine, showed that the vaccine candidate, called mRNA-1273, worked to trigger an immune response with mild adverse effects such as chills, headache, fatigue, muscle pain, and pain at the injection site.
Moderna’s vaccine is expected to begin a large Phase 3 trial later this month, which will be the final stage before the drug regulatory bodies consider whether to approve the vaccine.
On Tuesday, Moderna said if all goes well in future studies, “the company remains on track to be able to deliver approximately 500 million doses per year, and possibly up to 1 billion doses per year, beginning in 2021.”
Senior investigator Dr. Lisa Jackson said, “The goal was to look at safety and then to look at immune responses,” in the Phase 1 study.
“We thought the immune responses look promising, but we don’t know whether the levels we’re seeing would actually protect against infection. It’s really hard to know that until you do the actual efficacy trial,” she added. “So we’re laying the groundwork for the trial that will provide those answers.”
Moderna’s coronavirus vaccine is expected to be the first in the United States to enter into the Phase 3 trials.
The Phase 1 study included 45 healthy adults between the ages of 18 and 55, who received two doses of mRNA-1237 28 days apart. Some participants were enrolled at Kaiser Permanente in Seattle, while others at Emory University in Atlanta.
Dr. Jackson said, “The first dose sort of sets the immune system up, it’s called priming so that when you then administer the same thing again, there’s a booster response.”
“There’s an augmented response,” she added. “So we did not think that one vaccination would be sufficient to get the level of response that we wanted to see.”
She further explained that the team measured two types of immune responses. “Those two types of responses support each other,” she said.
“We know that the antibodies are being produced and it appears that there’s function after vaccination that serves to block the ability of the virus to enter cells,” Dr. Jackson added. “So it neutralizes the activity of the virus.”
However, some experts said more studies are needed to determine the safety and efficacy of mRNA-1273.
Dr. Paul Offit of NIH, who was not a part of the study, said, “What do we really want to know? We want to know whether the vaccine is safe and effective, that’s what we want to know.”
He said, “We know that it’s safe in 45 people, which is not going to be the 20 million people or 200 million people who are going to get it here in the United State. So we know that it doesn’t have a very common side effect problem, that’s what we know.”
“Then we don’t know anything about efficacy, which is what we really want to know,” Dr. Offit said. “Is this vaccine going to work? The only way to know that is to do a so-called Phase 3 trial.” According to the World Health Organization (WHO), Moderna’s experimental COVID-19 vaccine is one of 23 candidates in clinical trials around the world.
