China’s top disease control official has said the country is formally considering mixing Covid-19 vaccines, as a way of further boosting vaccine efficacy, Reuters reports.

The currently available vaccines “don’t have very high rates of protection”, Gao Fu, the director of the Chinese Centres for Disease Control and Prevention, told a conference in the Chinese city of Chengdu on Saturday. “Inoculation using vaccines of different technical lines is being considered.”

Gao said that taking steps to “optimise” the vaccine process including changing the number of doses and the length of time between doses was a “definite” solution to the efficacy issues.

“How to improve the protection rate of vaccines is a problem that requires global scientists to consider,” Gao said, adding that mixing vaccines and adjusting immunisation methods were solutions that he had proposed.