The Covid-19 booster vaccine programme has got under way in England and Scotland.
More than 700 care homes in England will be visited by vaccination teams from Monday, with thousands more jabs scheduled before the end of the month.
From Wednesday, around seven million people in England, including those aged 75 and over, the immunosuppressed and health and care workers will be able to book a jab via the internet or by calling 119.
In Scotland, care home residents are among those being offered the jab, while Wales has already started its programme and Northern Ireland will commence rollout later this month.
The NHS will contact people when it is their turn to book their vaccine.
Although infections are falling, health experts are predicting a resurgence of coronavirus this winter amid a possible worse flu season.
Two vaccines have been approved that can be used as boosters this autumn and winter – one from Moderna and the second from Pfizer.
Both have been approved by the Medicines and Healthcare products Regulatory Agency (MHRA) to target both the original and Omicron strains of the virus.
People who qualify for an autumn/winter booster include adults aged 50 and over, those aged five to 49 with health conditions that put them at greater risk, pregnant women, care home workers and frontline health and social care workers, carers and the household contacts of people with weakened immune systems.
NHS chief executive Amanda Pritchard said: “Once again, the NHS is kicking off a life-saving vaccination campaign to protect the nation ahead of winter, starting with those most vulnerable to serious illness and hospitalisation from Covid and flu.
“NHS staff have been working incredibly hard to prepare for the latest phase of the Covid vaccine rollout – the biggest and fastest in our 74-year history – with a record number of sites in local communities set to offer vaccinations to millions of people.
“When the booking service opens on Wednesday, don’t delay – the best way to protect yourself from serious illness this winter is to get the vaccine when invited to do so, as well as your annual flu jab if eligible.”