Over-75s, healthcare staff and patients with weakened immune systems were invited to book last week, with doses for that group being administered from today. More than a thousand care homes were also visited by vaccination teams last week.
A total of 26 million people in England will be eligible for a booster in the coming weeks. The rollout is happening in stages to ensure the most vulnerable are protected first.
NHS director of vaccinations and screening, Steve Russell said: “There is no room for complacency in keeping Covid-19 on the back foot, and this autumn booster will help protect those most at risk.
“From today those aged 65 and over, pregnant women and carers are now able to get their jab.
“If you are one of those eligible, it is as important as ever to get your next dose, so please do come forward as soon as possible.”
People who are eligible can book online or by calling 119 as long as it has been three months since they last received a Covid vaccination.
A record 3,100 sites are expected to help give the vital vaccinations, including GP practices, pharmacies and hospital hubs.
The NHS has delivered more than 126 million doses of Covid vaccines since the rollout began in December 2020.
Although the number of infections has been declining in the UK, experts fear they may rise again during the winter months as people spend more time indoors where the virus spreads more easily.
Southern hemisphere countries have also seen a resurgence of influenza after two years with little to no cases.
Flu vaccinations have begun and patients can receive both at the same time where possible.