A study by HKU researchers, details of which were published in the Lancet Microbe journal on Thursday, showed that antibody levels in healthcare workers who had received the BioNTech jab were ten times higher than in those who had received the Sinovac shot.
“For people who receive Sinovac and have relatively lower levels of antibodies, they may have less protection against infection, and in our study we’re going to continue following up these participants to see how long we can detect the antibodies for,” said Professor Benjamin Cowling.
He said they may need booster doses sooner, adding he was concerned that antibodies may not be detectable in these people after three or six months.
However, Cowling said it was premature for Hong Kong to think about booster shots now as the city should focus on vaccinating as many people as possible.
“Perhaps by the end of this year or by early next year, we would want to start thinking about booster doses and maybe the first groups of people who could get booster doses are the people who received Sinovac this year,” he said.
“Maybe later it might also be useful to offer booster doses to people who received the BioNTech vaccine, but that may be some time later.”
Cowling also dismissed suggestions it was a mistake for the Hong Kong government to have acquired Sinovac vaccines, pointing out that inactivated Covid-19 vaccines, including Sinovac, had saved many lives around the world.
“If there’s a choice between not getting vaccinated and getting Sinovac, it’s definitely much, much better to get Sinovac because there is protection against infection and there’s a high level of protection against severe disease,” he said.
“In Hong Kong, when we’re thinking about the alternatives, I would advise if you can get the BioNTech vaccine, get the BioNTech vaccine. I’ve said that all along, because it’s a more effective vaccine, gives a higher protection of vaccine that will likely last for longer.
“But if for some reason you can’t receive the BioNTech vaccine, or there’s another reason you don’t want to get the BioNTech vaccine, still it’s better to get the Sinovac vaccine than to not get vaccinated.”