NIH: Experimental COVID-19 vaccine safe, generates immune response

The first human study evaluating an mRNA COVID-19 vaccine made by Moderna Inc. produced neutralizing antibodies in healthy adults, who generally tolerated the vaccine well, the National Institutes of Health reports. The 45 participants received 25-, 100- or 250-microgram injections of the vaccine. The trial expanded to 120 participants in April, including the first adults over age 55. A phase 2 trial is underway to evaluate 50- and 100-microgram doses of the vaccine in 600 healthy adults, with plans to begin a large phase 3 trial of a 100-microgram dose this month.