Citing preliminary results from a real-world study, the UK Health Security Agency said that booster COVID-19 vaccine doses provide around 70% to 75% protection against mild disease caused by the new Omicron variant.

The early data from real-world evidence indicate that although Omicron variant of the coronavirus could decrease the protection against mild disease offered by an initial two-dose vaccination series considerably, booster doses could restore the protection to a certain extent.

In an evaluation of 581 individuals with confirmed Omicron infection, two doses of AstraZeneca and Pfizer-BioNTech COVID vaccines provided much lower levels of protection against symptomatic infection in comparison with that provided against Delta. When boosted with a dose of Pfizer vaccine, about 70% protection was noted against symptomatic infection for those who were initially administered AstraZeneca vaccine, while there was nearly 75% protection for individuals who had received the Pfizer vaccine initially… (ET Healthworld – Reuters, December 11, 2021)