Booster Shot Effective for 10 Weeks Against Omicron(UKHSA)[2021]

Booster protection against symptomatic illness caused by the Omicron variant dropped by up to 25% within 10 weeks, new real-world data found — though it's not yet clear whether everyone may need further doses in 2022.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1043807/technical-briefing-33.pdf

https://www.businessinsider.com/how-long-does-booster-protection-omicron-covid-last-study-2021-12