1. Analysis of omicron outbreak based on 211 000 covid-19 test results in South Africa. Discovery Health. 14 December 2021. www.discovery.co.za/corporate/news-room.
2. HKUMed finds Omicron SARS-CoV-2 can infect faster and better than delta in human bronchus but with less severe infection in lung. 15 December 2021. www.med.hku.hk/en/news/press/20211215-omicron-sars-cov-2-infection.