The Chinese Center for Disease Control and Prevention said 24 million doses of Chinese vaccines have been given in various countries. According to preliminary data, the rate of severe reactions is slightly lower than that of all other vaccines used in 2019. There were also fewer severe reactions than for flu vaccines. China's top respiratory disease expert said the vaccines are highly effective after the second dose. Zhong Nanshan said there have been no severe coronavirus cases among people who have received the vaccine during trials in various countries.