Covid booster shots could provide up to 75 percent protection against symptomatic infection from the Omicron variant.
That's according to the UK Health Security Agency.
In their real-world analysis, that looked at 581 people confirmed with Omicron, it found that two doses of AstraZeneca or Pfizer-BioNTech vaccines were less effective at stopping the new variant compared to Delta.
But that a third shot prevents around 75% of people getting any Covid symptoms.
Dr Susan Hopkins is the Chief Medical Advisor for the UKHSA:
"People who have had two doses more than three months ago are likely to get infection and transmit infection. What we see is after the booster dose, and that happens quite fast after the booster dose in early analysis from within 14 days, even up to just even seven days, that effect is reversed and actually what we are seeing is, no matter what your backbone, whether you had Astra(Zeneca) or Pfizer, you've got a 70-75% vaccine effectiveness for a symptomatic disease."
Hopkins went onto warn that at current growth rates, Omicron will account for more than half of all COVID-19 infections by mid-December, with Britain exceeding one million infections by the end of the month.
While no cases of Omicron have yet resulted in hospitalisation or death, the health agency says they still don't have enough data to assess the severity of the variant.
On Wednesday, Prime Minister Boris Johnson announced new measures to try to curb the spread of the disease.