People who are vaccinated against Covid-19 with BioNTech's vaccine were found to have "substantially higher" levels of antibodies than those who received Sinovac's jab, the South China Morning Post reported on Saturday, 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 Benjamin Cowling, an epidemiologist with the University of Hong Kong (HKU).