About the Sinovac, Sputnik V and Johnson & Johnson Covid-19 vaccines

An inactivated adenovirus is used as the vector to deliver the gene for the SARS-CoV-2 spike protein into the body in the Sinovac, Sputnik V, and Johnson and Johnson Covid-19 vaccines. — Wikimedia Commons

The efficacy of the Sinovac vaccine (officially named CoronaVac, but more popularly known by the name of its developer Beijing-based biopharmaceutical company Sinovac Biotech Limited) has been found to be to be 50.4% in preventing symptomatic Covid-19 by researchers in Brazil.

The director of the Chinese Center for Disease Control and Prevention himself has said that “Chinese vaccines don’t have very high protection rates”, and that the Chinese government is considering mixing the vaccines to give their efficacy a boost.