Moderna Inc’s experimental vaccine for COVID-19 showed it was safe and provoked immune responses in all 45 healthy volunteers in an ongoing early-stage study, US researchers reported on Tuesday, according to Reuters.
No study volunteers experienced a serious side effect, but more than half reported mild or moderate reactions such as fatigue, headache, chills, muscle aches or pain at the injection site.
These were more likely to occur after the second dose and in people who got the highest dose, the team reported in the New England Journal of Medicine.
Moderna was the first to start human testing of a vaccine for the novel coronavirus on March 16, some 66 days after the genetic sequence of the virus was released.
Experts say a vaccine is needed to put an end to the pandemic that has sickened millions and caused nearly 575,000 deaths worldwide.
“The world urgently needs vaccines to protect against COVID-19,” said Dr Lisa Jackson of Kaiser Permanente Washington Health Research Institute in Seattle and lead author of the study.
The federal government is supporting Moderna’s vaccine with nearly half a billion dollars and has chosen it as one of the first to enter large-scale human trials.
Moderna’s shot, mRNA-1273, uses ribonucleic acid (RNA) - a chemical messenger that contains instructions for making proteins. When injected into people, the vaccine instructs cells to make proteins that mimic the outer surface of the coronavirus, which the body recognizes as a foreign invader, and mounts an immune response against.
The results released on Tuesday involved three doses of the vaccine, tested in groups of 15 volunteers aged 18-55 who got two shots, 28 days apart. The groups tested 25, 100 or 250 micrograms of the vaccine.
In April, Moderna expanded the Phase 1 trial to include adults over 55, who are more at risk of serious disease, with the aim of enrolling 120 volunteers. Moderna said it will follow study volunteers for a year after the second shot, to look for side effects and check how long immunity lasts.