2 stickers with the words 'I've Booster My Immunity Flu Vaccine + COVID-19 Booster', given out at Bidborough House NHS Vaccination Centre, 2021

During winter 2021, everyone who was eligible to receive a free flu vaccine and a COVID-19 booster was encouraged to do so. Scientific research suggested that there was a possibility of a flu surge coinciding with increasing numbers of COVID-19 cases. This was based on colder weather, which aids transmission, increased indoor socialisation and less windows being open. Fewer people had flu in 2020 due to lockdown restrictions so immunity was generally lower.

COVID-19 boosters were offered in winter 2021, originally to anyone over aged 50 or in a priortity group and were eventually rolled out to everyone.