Moderna’s experimental vaccine for COVID-19 was shown to be safe and elicited immune responses in the 45 healthy volunteers in an ongoing early-stage study, US researchers reported Tuesday.
No study volunteer experienced a serious side effect, but more than half reported mild or moderate reactions such as fatigue, headache, chills, muscle aches, or injection site pain.
They were more likely to occur after the second dose and in people who received the highest dose, the team reported in the New England Journal of Medicine (NEJM).
Moderna was the first American company to begin human testing of a vaccine for the new coronavirus on March 16, about 66 days after the release of the virus’ genetic sequence.
Moderna’s experimental coronavirus vaccine triggered an immune response and caused only minor side effects in a trial of 45 healthy volunteers, according to results published Tuesday.
Experts say a vaccine is needed to end 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 the Kaiser Permanente Washington Health Research Institute in Seattle and lead author of the study.
The federal government supports the Moderna vaccine with nearly half a billion dollars and has chosen it as one of the first to participate in large-scale human trials. A successful vaccine could be a turning point for Cambridge, Massachusetts-based Moderna, which has never had a licensed product.
Moderna’s injection, 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 generates an immune response against it.
Results published Tuesday included three doses of the vaccine, tested in groups of 15 volunteers ages 18 to 55 who received two injections, 28 days apart. The groups tested 25, 100, or 250 micrograms of the vaccine.
The team reported that people who received two doses of the vaccine had high levels of neutralizing antibodies that kill viruses that exceeded the average levels seen in people who had recovered from COVID-19.
Adverse events after the second dose occurred in seven of the 13 volunteers who received the 25 microgram dose, the 15 participants who received the 100 microgram dose, and the 14 who received the 250 microgram dose.
In the highest dose group, three patients had severe reactions such as fever, chills, headache, or nausea. One of them had a fever of 103.28 Fahrenheit (39.6 C).
“We didn’t see any events that are characterized as serious adverse events,” Jackson said, referring to reactions that require hospitalization or death.
In June, Moderna said it selected the 100 microgram dose for its late-stage study to minimize adverse reactions.
At that dose, Moderna said the company is on track to deliver around 500 million doses per year, and possibly as much as a billion doses per year, starting in 2021, from the company’s internal manufacturing site in the US And the strategic collaboration with the Swiss drug maker Lonza.
“It’s a good first step,” said Dr. William Schaffner, a vaccine expert at Vanderbilt University Medical Center who was not involved in the study.
“There is nothing here that prevents one from advancing to Phase 2 / Phase 3 testing,” he said.
“A little fatigue, headache, and myalgia (muscle pain) and pain at the injection site is a small price to pay for protection against COVID-19.”
In April, Moderna expanded the Phase 1 trial to include adults over the age of 55, who are at increased risk for severe disease, with the goal of enrolling 120 volunteers.
Moderna said she will follow the study volunteers for a year after the second injection, to look for side effects and to check how long the immunity lasts. (Report by Julie Steenhuysen in Chicago Edited by Matthew Lewis)
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