Study Seems To Show Chinese COVID-19 Vaccine Only 50% Effective, Prompting Clarification From China

Brazil's Butantan Institute released numbers calling into question the efficacy of China's CoronaVac vaccine Wednesday, prompting China to respond in order to clarify the numbers. Butantan is in final-stage trials for CoronaVac, a COVID-19 vaccine manufactured by China's SinoVac, and submitted results to Brazilian regulators Tuesday declaring an efficacy rate of just over 50%, according to the South China Morning Post . A week prior, Butantan, a partner of SinoVac, submitted results indicating CoronaVac was 78% effective in preventing mild cases of COVID-19 and 100% effective in preventing severe cases, according to SCMP. How effective is China's Sinovac vaccine? Experts…