Beijing: China’s Center for Disease Control and Prevention has raised the prospect of mixing vaccines and varying doses to boost efficacy, the first time a government body has acknowledged concerns over the effectiveness of domestic jabs. Gao Fu, the CDC’s head, said that the agency was “considering how to solve the problem that the efficacy of existing vaccines is not high”. Gao proposed mixing different vaccines as well as changing the number of doses and amending the interval between them.
Any new strategy will have ramifications for the more than 20 countries that China said it was supplying in bilateral “vaccine diplomacy” deals. As of March, China had supplied 40mn doses to countries across the globe, including Brazil, Serbia and the United Arab Emirates, prompting the US and its allies to launch their drive to supply 1bn doses of Johnson & Johnson’s Covid-19 vaccine to south-east Asian nations.
Chile, which has relied on China’s Sinovac jab for its vaccine drive, is in the middle of another Covid-19 wave arising from new variants. It has administered 62 doses per 100 residents, the third-highest rate in the world. A recent study of the effectiveness of Chile’s vaccination programme found the efficacy of a single dose of the Sinovac jab was only 3 per cent, compared with 56 per cent with two shots. However, local health experts have not linked the latest wave to the vaccine’s efficacy rate.
Social-media posts on Gao’s remarks were swiftly censored, according to Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations. “It is the first time . . . a government official publicly admitted that the protection rate is a concern in the vaccination drive,” Huang added. China had administered 65mn doses across the country by the middle of March. Unlike other vaccine producers, China’s manufacturers have not published their phase 3 trial data, leading to accusations of a lack of transparency on the vaccine’s effectiveness on different groups.
Sinopharm claims a 79 per cent efficacy rate, similar to those achieved by AstraZeneca in its US trials. Sinovac’s vaccine has an overall efficacy rate of 51 per cent among people aged 18 to 60, according to documents published by a Hong Kong panel of experts. Peter English, a retired communicable disease control consultant at Public Health England, said it was “astonishing” that phase 3 trial data for the Chinese vaccines had not yet been published.
