Moderna’s Covid-19 Vaccine Shows Promise

September 5, 2020

An experimental COVID-19 vaccine from biotech firm Moderna showed promising results in early trials with 45 participants, according to the company’s first trial data published in a peer-reviewed journal.

After receiving two doses of the vaccine, called mRNA-1273, all participants developed so-called neutralizing antibodies, which prevent new coronaviruses from infecting cells. According to the study, published Tuesday (July 14) in the New England Journal of Medicine, participants had higher levels of these antibodies in their blood than the average level in recovered COVID-19 patients.

The results of this early Phase 1 trial support the company’s results released in May, which were not published in a peer-reviewed journal at the time.

The vaccine was developed in collaboration with the National Institutes of Health and is the first vaccine to be tested on humans in the United States. According to the New York Times, the company has begun more advanced trials of the vaccine, known as Phase 2 trials, and plans to begin a large Phase 3 trial with 30,000 participants on July 27.

The current study involves healthy participants between the ages of 18 and 55, who were vaccinated at locations in Seattle and Atlanta. Participants were divided into three groups (15 in each group) and received either a low dose (25 micrograms or micrograms), a medium dose (100 micrograms), or a high dose (250 micrograms) of the vaccine.

The vaccine appeared to be safe and participants generally tolerated it, although more than half experienced some side effects, including fatigue, chills, headaches, muscle aches, and pain at the injection site. (To put this in perspective, many of these side effects are also present in the annual flu vaccine.) Some participants in the intermediate and high-dose groups experienced a fever after the second injection. (Fever is also a side effect of the flu vaccine, albeit a rare one.)

One participant in the high-dose group experienced a “severe” fever of 103 degrees Fahrenheit (39.4 degrees Celsius). The participant also experienced nausea, dizziness and one fainting episode, but felt better a day and a half later, according to the Los Angeles Times.

The data on side effects and immune response seen in this study helped researchers refine the vaccine doses used for the Phase 2 and Phase 3 trials. The authors said the phase 2 trial will look at doses of 50 micrograms to 100 micrograms, and the phase 3 trial is expected to look at doses of 100 micrograms.

The Phase 3 study is expected to be completed in October, but may take more time to prove the vaccine is safe and effective, according to The New York Times. Ideally, researchers hope to prove that people who receive the vaccine are unlikely to develop COVID-19, and the fastest way to do that may be to test the vaccine in COVID-19 “hot spots,” according to the New York Times.