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Last week more than 200,000second doses were given, NHS England said. Fifty-five per cent of those who received them had delayed it for five or more weeks after becoming eligible.
It is estimated that about 1.1 million adults in England have had their first dose only, even though they are now eligible for a second shot.
More than 40 million people have received both doses of the vaccine in England.
NHS England said that last week more than 65,000 people had their first Covid-19 shot.
“The offer of a Covid-19 jab in the NHS vaccination programme is evergreen and it is fantastic that we have now given two or more doses to 40 million people across England, including 205,000 last week alone," said Dr Emily Lawson, vaccination lead for the service.
“We know people are busy and over half of people put off having their second dose in the run-up to Christmas.
“NHS staff are making it as easy as possible for people to get the vaccine in their local communities and it’s never too late to get any of your doses of protection, whether it’s first, second or third.
“Vaccination continues to be our best protection against serious illness, so I encourage anybody who isn’t vaccinated or is still to get their second dose to come forward without delay to get the best protection on offer against coronavirus.”
“I am incredibly proud of our phenomenal vaccination programme, from NHS frontline staff and volunteers to the armed forces and British public, who have done everything they can to get jabs into arms as quickly as possible," said UK Health Secretary Sajid Javid.
“Every one of us has a part to play in the national mission to make sure we’re all protected.
“The offer of a vaccine will always be there – whether it’s your first dose, second dose or your booster. Please keep coming forward.”