One of the first large studies of safety and effectiveness of a coronavirus vaccine in the United States began on Monday morning, according to the National Institutes of Health and the biotech company Moderna, which collaborated to develop the vaccine.
The study, a Phase 3 clinical trial, is to enroll 30,000 healthy people at about 89 sites around the country. Half will receive two shots of the vaccine, 28 days apart, and half will receive two shots of a saltwater placebo. Neither the volunteers nor the medical staff giving the injections will know who is getting the real vaccine.
Researchers will then monitor the subjects, looking for side effects and waiting to see if significantly fewer vaccinated people get Covid-19, indicating that the vaccine works. The main goal is to determine whether the vaccine can prevent the illness. The study will also try to find out if it can prevent severe Covid-19 and death; if it can prevent infection entirely, based on lab tests; and if just one shot can prevent the illness.
Earlier tests of the vaccine showed that it stimulated a strong immune response, with minor and transient side effects like sore arms, fatigue, achiness and fever. But exactly what type of immune response is needed to prevent the illness is not known, so Phase 3 studies are essential to determine whether a vaccine really works.
In a statement, Dr. Francis Collins, the director of the N.I.H., said, “Having a safe and effective vaccine distributed by the end of 2020 is a stretch goal, but it’s the right goal for the American people.” He said that despite the unprecedented speed in bringing this experimental vaccine to human testing, “the most stringent safety measures” were being maintained.
Moderna said in a statement that it would be able to deliver about 500 million doses per year, and possibly up to a billion doses per year, starting in 2021. The company says it will not sell the vaccine at cost, but for profit.
The vaccine uses a synthetic version of genetic material from part of the coronavirus, encased in tiny particles made of fat that help it get into human cells. The genetic material, called messenger RNA or mRNA, then prompts the cells to churn out a tiny piece of the virus, which the immune system sees as foreign, and learns to recognize. If the person is later exposed to the real virus, the immune system will attack.