New Coronavirus Vaccine Candidate Shows Promise In Early, Limited Trial

Joe Palca

May 18, 2020 / 9:46 am

caption: A view of Moderna headquarters in Cambridge, Mass., earlier this month. Moderna is touting preliminary data from an initial coronavirus vaccine trial.

A vaccine manufacturer is reporting preliminary data suggesting its COVID-19 vaccine is safe, and appears to be eliciting in test subjects the kind of immune response capable of preventing disease.

Moderna, Inc., of Cambridge, Mass., developed the vaccine in collaboration with the National Institute of Allergy and Infectious Diseases. The results reported Monday come from an initial analysis of a Phase I study primarily designed to see if the vaccine is safe.

The company reports no serious side-effects; however, modest side-effects included redness at the injection site, headache, fever and flu-like symptoms, although none of these lasted more than a day.

The first 45 volunteers for the vaccine trial were divided into three groups, with each group getting a different dose of the vaccine. All groups got an initial shot, followed by a booster shot a month later.

In addition to safety, the company also looked at the vaccine's ability to induce antibodies to the coronavirus — what's known as its immunogenicity. It did, for all subjects at all dose levels. In addition, eight of the subjects were tested for the presence of neutralizing antibodies that prevent the virus from infecting cells in the laboratory. All eight did.

The Food and Drug Administration has given Moderna the green light to begin a Phase II study expected to enroll an additional 600 volunteers — half older than 55 — to provide additional immunogenicity data. The company hopes by July to begin a Phase III study, aimed at showing that the vaccine can actually prevent disease.

The Moderna vaccine is made using messenger RNA, or mRNA, a molecule containing the genetic instructions to make a protein on the coronavirus surface that is recognized by our immune systems. Although mRNA vaccines have been studied for several years, so far none has been licensed by the FDA.

The advantage of mRNA vaccines over more traditional vaccines is they can be made quickly. The company says it was just 63 days from the time Chinese scientists revealed the genetic sequence to the time a vaccine was injected into the first volunteer.