People who are vaccinated against Covid-19 with BioNTech's vaccine are found to have "substantially higher" levels of antibodies than those who have received Sinovac's jab, the South China Morning Post has reported, citing a Hong Kong study.

Some who received the Sinovac vaccine might need a third booster shot as well, the newspaper said, citing lead researcher Professor Benjamin Cowling, an epidemiologist with the University of Hong Kong (HKU).

The government-commissioned study was conducted by HKU's school of public health and involved tracking the antibody responses of 1,000 people who received either vaccine, Reuters quoted the report as saying.