A single dose of the Sinovac and Sinopharm vaccines is only 13.8 per cent effective against the new Delta variant, a recent study conducted in Guangzhou, China shows.
The research shows that while two shots of the Chinese vaccines are effective at, 59 per cent in preventing the Delta strain and 70.2 to 100 per cent effective at preventing severe symptoms caused by the variant, a single shot of the vaccines was only 13.8 per cent effective in preventing COVID-19 infections.
The research shows that two doses are the minimum necessary to fight the new Delta variant and prevent severe symptoms, said Zhong Nanshan, China’s leading epidemiologist and co-author of the study.
The report was based on real-world data collected in Guangzhou between May 18 and June 20.
The report has ramifications for Thailand which has chosen to continue to buy Sinovac vaccines despite their lower efficacy and higher cost.
The Thai government has defended the decision by saying that they were the only vaccines that are available now and that other vaccines would take months to arrive.
The government has been much scrutinzied and criticized for its vaccine acquisition program and its red-tape in preventing private hospitals from importing their own vaccines.