China considers mixing COVID-19 vaccines to boost protection rate

BEIJING, (Reuters) - 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.

Available data shows Chinese vaccines lag behind others including Pfizer and Moderna in terms of efficacy, but require less stringent temperature controls during storage.

Giving people doses of different vaccines is one way to improve vaccines that “don’t have very high rates of protection”, Gao Fu, the director of the Chinese Centers for Disease Control and Prevention, said on Saturday, without specifying whether he was referring to foreign or domestic vaccines

“Inoculation using vaccines of different technical lines is being considered,” Gao told a conference in the Chinese city of Chengdu.

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 efficacy issues.

Two injections of a vaccine developed by China’s Sinovac Biotech, when given shorter than three weeks apart, was 49.1% effective based on data from a Phase III trial in Brazil, below the 50% threshold set by World Health Organization, according to a paper published by Brazilian researchers on Sunday ahead of peer review.

But data from a small subgroup showed that the efficacy rate increased to 62.3% when the doses were given at intervals of three weeks and longer. The overall efficacy rate for the vaccine was slightly above 50% in the trial.