Moderna’s Covid-19 Vaccine Spurs an Immune Response in Healthy People
But it came with some side effects
An experimental Covid-19 vaccine developed by biotech company Moderna spurred immune responses in a small number of healthy people. But the two-shot regimen also gave some people in the trial mild side effects like fever and headache.
On March 16, Moderna became the first company in the United State to begin human testing of a vaccine for the novel coronavirus. The much-anticipated but preliminary results of that early-stage trial were published by U.S. government researchers in the New England Journal of Medicine on Tuesday.
The trial, which is being conducted by the National Institutes of Health, initially included 45 adults ages 18 to 55 years old. They were divided into three groups that each got a different dose. Everyone in the trial received one injection, and 42 people received a booster shot four weeks later.
After the first dose, people started producing binding antibodies against SARS-CoV-2, the virus that causes Covid-19. While these binding antibodies don’t provide protection, they’re evidence that the immune system responded to the vaccine. It wasn’t until two weeks after the booster shot that researchers detected antibodies of a different kind: those capable of neutralizing the virus. Scientists think these neutralizing antibodies could provide immunity. The levels of both kinds of antibodies observed in the trial participants were similar to levels found in blood plasma from people who recovered from Covid-19.
The researchers don’t yet know if the immune responses are long-lasting. They plan to follow participants in this initial trial for a year after their second vaccination and measure antibody levels in their blood periodically.
Though the immune responses look promising, more than half of the people in the trial reported side effects like fatigue, headache, chills, or soreness or pain in their injected arm. None of these side effects were considered serious, meaning they did not result in disability or hospitalization and were not life-threatening.
Following the first vaccine dose, one person withdrew from the trial after developing hives. After the second injection, six people…