Researchers are testing 64 coronavirus vaccines in clinical trials on humans. Here are explanations about how eight of the leading vaccines work.
Messenger RNA Vaccines
How the Pfizer-BioNTech Vaccine Works
The vaccine, known as Comirnaty, has been approved or authorized for emergency use in several countries, including the United States. Clinical trials showed the vaccine has an efficacy of 95 percent.
The vaccine, known as mRNA-1273, has been approved in Canada and authorized for emergency use in the United States. Clinical trials showed the vaccine has an efficacy of 94.5 percent.
Adenovirus-Based Vaccines
Protein-Based Vaccines
Inactivated Coronavirus Vaccines
How the Sinopharm Vaccine Works
The vaccine, known as BBIBP-CorV, is authorized for limited use in China. Sinopharm says the vaccine has an efficacy rate of 79.34 percent.
New · How Bharat Biotech’s Vaccine Works
The vaccine, known as Covaxin, is authorized for emergency use in India, despite a lack of published Phase 3 trial results. The vaccine’s efficacy is not yet known.
See the Coronavirus Vaccine Tracker for the status of other vaccines in development.
Tracking the Coronavirus