More than 1.6 million people who are newly eligible for a coronavirus booster vaccine will be invited to come forward next week.
Around 9.5 million booster invites have been sent to people in England so far, and more than six million jabs have been delivered in the first six weeks of the rollout, according to NHS England.
More than half of eligible people aged over 50 and over two thirds of people over 80 have received the third dose, the service said.
Deputy lead of the NHS vaccination programme, Dr Nikki Kanani, said the figures are “encouraging” and advised anyone who receives an invite to take up the offer.
Dr Kanani said: “It is encouraging to see that thanks to the efforts of NHS staff, millions of people have received their booster already and just over six weeks in, with over half of eligible over 50s already protected as we head into winter like no other.
“I’ve recently had my booster at a local pharmacy and with more people becoming eligible every day I would encourage anyone who receives their text or letter invite to book an appointment and get their potentially life-saving top-up jab as soon as they can.
“The vaccine is simple, quick and effective and will help us to give the country maximum protection from the virus.”
People who are eligible for boosters will be invited for the shot at least six months after their second dose, so the number of eligible people changes daily.
Text invites will come from “NHSvaccine” and will include a link to the NHS website, guiding people to their nearest vaccine site.