Pfizer Says Experimental COVID-19 Vaccine Is More Than 90% Effective

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

That news comes from an interim analysis of a study involving 43,538 volunteers, 42% 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....