The national medical director for the NHS is urging the over-50s and those at risk to book their Covid-19 vaccines quickly before slots dry up.
Professor Stephen Powis called on anyone who qualifies for a jab but has not yet received a first dose to book an appointment in the next few days.
The NHS is expecting a slowdown in UK vaccine supply for the whole of April, meaning medics will concentrate on delivering second doses, with fewer first appointments available.
NHS England has said no first appointments should be booked for people under the age of 50 unless they fall into a higher priority group, such as those who are clinically vulnerable.
Prof Powis said: “It is a testament to the careful planning and sheer hard work of staff that the NHS vaccination programme is continuing to protect people against coronavirus at a record pace.
“I was thrilled to get my first dose earlier this month, it was quick, painless and safe and it feels great knowing I’ve got protection against Covid-19 – so if you are eligible, do not delay, book a jab.”
Around seven in 10 people aged 50 to 54 have now had a first dose of a vaccine, according to NHS England.
Anybody aged 50 or over can book themselves in for a first dose before March 29 online using the national booking system for England.
People aged 18 and over who are clinically vulnerable should also book themselves in for a vaccine.
GPs will continue contacting eligible patients on their lists and offering vaccines to anyone who has not had one so far.