According to the Associated Press, the FDA is mobilizing to authorize a second COVID-19 vaccine.  The vaccine has been co-manufactured by the drug company Moderna and its partner the National Institutes of Health.

Like the Pfizer-BioNTech Vaccine, the Moderna vaccine employs messenger RNA technology, which means it instructs cells to make a protein that triggers an immune response.  The two vaccines are also alike because they require two doses to complete. 

Both vaccines need to be kept cold, but NPR reports that the Pfizer vaccine needs to be stored at minus 70 degrees Celsius, whereas the Moderna vaccine needs to be stored at minus 20 degrees Celsius.

To understand more about how the Moderna vaccine works, check out this article by the New York Times.