The latest variant technical briefing suggests that Omicron continues to grow rapidly in all regions of England as measured by confirmed cases and S gene target failure (SGTF). None of the cases to date is known to have been hospitalised or died.
Studies of contacts show that Omicron is transmitting more effectively than Delta. The UK Health Security Agency (UKHSA) estimates that if Omicron continues to grow at the present rate, the variant will become the dominant strain, accounting for more than 50% of all COVID-19 infections in the UK by mid-December. It is projected that if current trends continue unchanged, the UK will exceed one million infections by the end of this month.
The technical briefing also includes early analysis of vaccine effectiveness against the Omicron variant compared to Delta.
The analysis looked at 581 people with confirmed Omicron. It showed that the AstraZeneca and Pfizer-BioNTech vaccines provided much lower levels of protection against symptomatic infection compared to the protection that they provide against Delta. However, the preliminary data showed effectiveness against the new variant appears to increase considerably in the early period after a booster dose, providing around 70% to 75% protection against symptomatic infection.
