A joint study by HKUMed and CU Medicine reveals that Omicron variant significantly reduces the virus neutralisation ability of Pfizer BioNTech vaccine by 32 folds or more. A similar test on CoronaVac is being conducted. Vaccines are still likely to protect against death and severe disease. High-risk groups are urged to get booster doses. The research team will be testing blood of those who have received a booster dose in the coming week.