On Jul. 21, 2020, researchers announced that early results from the first COVID-19 vaccine candidate tested in people showed that it triggered an immune response against the virus with no serious side effects. Scientists began Phase 1 trials of an experimental vaccine for COVID-19 in mid-March.

The vaccine, called mRNA-1273, is being co-developed by researchers at NIH’s National Institute of Allergy and Infectious Diseases (NIAID) and the biotech company Moderna.