This is part of an effort to get as many people vaccinated as possible before restrictions are relaxed in England on July 19.
Text messages will be sent to 650,000 people telling them they need to make sure their second appointment for the vaccine is no more than eight weeks after their first.
Initially, vaccine doses were set aside up to 12 weeks apart, in an effort to boost immunity while spreading a tight supply among more people.
But the Joint Committee on Immunization and Immunization (JCVI) has since changed its position to say that people should aim to receive their second dose between eight and 12 weeks later.
Experts said, however, that there was “no gain” in bringing the interval between doses closer together.
JCVI Vice President Professor Anthony Harnden told Times Radio on Wednesday: “It’s pretty clear from the T cell antibody studies that you get a much weaker response and less memory response. good quality with a shorter interval – that’s a four week interval versus an eight to twelve week interval.
“And real vaccine efficacy studies with real data show that there is lower vaccine efficacy against symptomatic diseases with shorter intervals compared to longer intervals.
“Then we asked the modelers to look at that and in fact the number of infections will increase if we reduce the dose. “
Sir Keith Willett, England’s COVID-19 Vaccination Program Manager, said: ‘Thanks to the hard work of NHS staff and volunteers across the country, almost two-thirds of people in England have already received two doses vaccine.
“The second crucial dose provides maximum protection against the virus and it will protect you, your family and those around you.
“As July 19 approaches, there has never been a more important time to get stung and it has never been easier -om pop-up sites in the community to walking centers, NHS makes as great a dresser as possible.
“So I urge everyone to bring their second dose appointments forward to eight weeks as soon as they can. “
Health Secretary Sajid Javid said: “Getting that second vital blow will also allow us to get back to doing things we missed, like going on vacation. Everyone should seize the opportunity as soon as possible so that we can all start enjoying the freedoms that we have been missing. “
Text invitations appear as an ‘NHSvaccine’ alert and include a web link to the NHS website to book an appointment.
People who can’t log in can call service on 119 instead to reserve their jab.