Sinovac maker advises longer gaps between doses

Chinese COVID-19 vaccine maker Sinovac said it recommends longer intervals between two doses to achieve better effectiveness after the country's top CDC official admitted the weakness of Chinese coronavirus vaccines.

Liu Peicheng, Spokesperson for Sinovac, one of the Chinese COVID-19 vaccine producers that have distributed millions of doses domestically and in other countries, acknowledged at a press conference on Sunday that varying levels of effectiveness have been found.

Liu added that the significant variations in effectivness found in different places could be due to the age of people in a study, the strain of virus and other factors.

The effectiveness of a Sinovac vaccine at preventing symptomatic infections was found to be as low as 50.4% by researchers in Brazil, near the 50% threshold at which health experts say a vaccine is useful. By comparison, the Pfizer-BioNTech vaccine has been found to be 97% effective.

In a rare admission of the weakness of Chinese coronavirus vaccines, the country's top disease control official on Saturday said that their effectiveness is low and the government is considering mixing them to get a boost.

Chinese vaccines “don’t have very high protection rates,” said the director of the China Centers for Disease Control, Gao Fu, at a conference Saturday in the southwestern city of Chengdu.

Beijing has distributed hundreds of millions of doses abroad while trying to promote doubt about the effectiveness of the Pfizer-BioNTech vaccine made using the previously experimental messenger RNA, or mRNA, process.

Officials at a news conference Sunday didn’t respond directly to questions about Gao’s comment or possible changes in official plans.

But another CDC official said developers are working on mRNA-based vaccines.

Experts say mixing vaccines, or sequential immunisation, might boost effectiveness.

Researchers in Britain are studying a possible combination of Pfizer-BioNTech and the AstraZeneca vaccine.

The coronavirus pandemic, which began in central China in late 2019, marks the first time the Chinese drug industry has played a role in responding to a global health emergency.

Vaccines made by two state-owned drug makers, Sinovac and Sinopharm, have been exported to 22 countries including Mexico, Turkey, Indonesia, Hungary, Brazil and Turkey, according to the foreign ministry.

Health experts say Chinese vaccines are unlikely to be sold to the United States, Western Europe and Japan due to the complexity of the approval process.

Beijing has yet to approve any foreign vaccines for use in China.