Health teams will visit more than 800 schools across England this week to offer children aged 12-15 a coronavirus vaccine.
Many more pupils returning to classrooms after the October half-term break can get a jab at school, NHS England said.
Alternatively, children can make an appointment to visit a vaccination centre using the national booking system which has also been opened to this age group.
NHS teams are set to visit hundreds of schools in the next week to offer children a jab.
More than 600,000 young people have been vaccinated since the jabs rollout was extended to include 12 to 15-year-olds at the end of September, NHS England said.
Some 163,000 young people received a jab in the week after the national booking system opened up to them from October 22.
A further 140,000 children have their vaccine booked over the next few weeks, NHS England added.
Health Secretary Sajid Javid said: “The vaccines are safe and will help keep children in the classroom – I encourage everyone to come forward for their jab to protect themselves and the people around them.”
Dr Nikki Kanani, GP and deputy lead for the NHS Covid-19 vaccine programme, said: “As our children return to the classroom, our efforts to vaccinate children will not stop – hundreds more schools will be vaccinating this week.
“It’s really important that we continue with the same enthusiasm if we want to ensure children get to stay in the classroom with their fellow pupils this winter, and so I encourage all parents and guardians to head online and read the information on vaccinating your child, so you can make an informed decision.”
Pupils are also being urged to get tested for coronavirus before returning to school to minimise disruption to lessons and to ensure families can “enjoy the best” of the festive season.
Ministers and the UK Health Security Agency are calling on young people to take a rapid lateral flow test before the end of the October half-term to help prevent Covid-19 entering the classroom.