Omicron: China’s Sinovac says third shot could help fight variant, as Hong Kong study fails to reveal antibodies with two

• About 94 per cent of people with a third dose had detectable levels of antibodies, Sinovac says, after HKU study finds none in 25 people on two-dose regimen
• The Pfizer-BioNTech vaccine also showed a ‘significant’ immune response drop and boosters may be needed for both, researchers said