BEIJING (Reuters) – China’s top disease control official has said the country is formally considering mixing COVID-19 vaccines as a way to further increase the effectiveness of vaccines.
Available data show that Chinese vaccines lag behind others, including Pfizer and Moderna in terms of efficacy, but require less stringent temperature controls during storage.
Giving people different doses of vaccines is a way to improve vaccines that “do not have very high protection rates,” Gao Fu, director of China’s Centers for Disease Control and Prevention, said Saturday, without specifying whether he was referring to national vaccines. or foreigners.
“Inoculation with vaccines of different technical lines is being considered,” Gao said at a conference in the Chinese city of Chengdu.
Gao said taking steps to “optimize” the vaccination process, including changing the number of doses and the length of time between doses, was a “definitive” solution to efficacy problems.
Two injections of a vaccine developed by China’s Sinovac Biotech, when administered less than three weeks apart, were 49.1% effective according to data from a phase III trial in Brazil, below the threshold. 50% set by the World Health Organization, according to a paper released by Brazilian researchers on Sunday before the peer review.
But data from a small subgroup showed that the efficacy rate increased to 62.3% when doses were given at intervals of three weeks and more. The overall efficacy rate of the vaccine was slightly above 50% in the trial.
China has developed four approved domestic vaccines for public use and a fifth for small-scale emergency use. An official said Saturday that the country is likely to produce 3 billion doses by the end of the year.
No detailed data have been published on the efficacy of vaccines manufactured by Sinopharm of China. It has been said that two vaccines developed by their units are 79.4% and 72.5% effective, respectively, according to the intermediate results.
Both vaccine manufacturers have submitted data on their COVID-19 vaccines that indicate levels of efficacy in line with those required by the WHO, a WHO group said in March.
China has sent millions of its vaccines abroad and state officials and media have fiercely defended the shots while questioning the safety and logistical capability of other vaccines.
“Global vaccine protection rate testing data is high and low,” Gao told the state-run Global Times on Sunday.
“How to improve the rate of vaccine protection is a problem that global scientists need to take into account,” said Gao, who added that mixing vaccines and adjusting immunization methods are solutions he had proposed.
Gao also dismissed claims by some media outlets that Chinese COVID-19 vaccines have a low protection rate, and told the Global Times that it was “a complete misunderstanding.”