In a surprising move, the director of the China Centers for Disease Control, Gao Fu, has admitted that Sinovac vaccines had low effectiveness and that the government is considering mixing them in a bid to increase their efficacy.
“It’s now under formal consideration whether we should use different vaccines from different technical lines for the immunization process,” he said. It was not clarified whether these ‘different vaccines’ would be foreign-made ones.
Other “definite” solutions to the issue of efficacy were changing the number of doses as well as changing the length of time between doses, Gao also said. Experts suggest mixing vaccines or sequential immunization may help effectiveness rates increase.
While data from Brazilian researchers found the vaccine’s efficacy to be at 49.1%—below the World Health Organization’s 50% threshold—when given shorter than three weeks apart, data from a small subgroup showed that the rate rose to 62.3% when given three weeks or more, apart.
Despite the low efficacy rate, a separate key Brazilian study showed that the Sinovac jab cut the risk of symptomatic Covid in half.
The trial, which involved nearly 10,000 participants strengthened findings from a larger Brazilian study released last week, which demonstrated a 50% protection rate with 14 days in between the two doses.
Head of epidemiology and biostatistics at the University of Hong Kong, Benjamin Cowling, said that rollout of approved vaccines should continue.
“They can provide a high level of protection, particularly against severe Covid,” he said.
Beijing has shipped hundreds of millions of doses to other nations, many of them in Africa, South America, and some Asian countries, including the Philippines.
On April 11, the country received the second shipment of Sinovac vaccines purchased from China, following the first shipment of 1 million doses that arrived last March 29.