Pfizer's experimental COVID-19 vaccine is more than 90% effective

President Trump promised that a vaccine would be ready soon when he was on the campaign trail. 

From NPR:

Pfizer's experimental COVID-19 vaccine appears to be working. The vaccine was found to be more than 90% effecting, according to clinical results released by the company Monday. 

That news comes from an interim analysis of a study involving 43,538 volunteers, 42 percent of whom had "diverse backgrounds." Each participant got two injections spaced 21 days apart. 

The analysis compared the number of cases of COVID-19 among the volunteers getting the vaccine, with an approximately equal sized group of volunteers who got an injection of a liquid that didn't contain the vaccine. 

In a news release from Pfizer and its partner BioNTech, the company said results from 94 evaluable cases of COVID-19 among study participants indicated the more than 90 percent effective in preventing COVID-19. The Food and Drug Administration set a minimum effectiveness bar at 50%.