Booster jabs will be available to book for those who need them a month earlier than expected in England, in an effort to speed up the programme, the government has announced.

Those eligible for the top-up vaccination will receive their booking invitation five months after their second dose instead of six, after a change to the system means boosters can be prebooked.

Office for National Statistics figures show that the prevalence of coronavirus infections in England remained at about 1 in 50 people in the week ending 30 October, steadying at its highest level of the year. Prevalence was unchanged from the previous week, after five weeks of rising infections.

Infection rates decreased for older secondary school pupils over the week, the ONS said, dropping to 7.5% from 9.1% the previous week.

Other suggestions that the spread of Covid is slowing include England’s R number falling to between 0.9 and 1.1, down from a previous estimate of 1.1-1.3.

More than 9m top-up jabs have already been administered across the UK and from Monday, the English booking system will allow someone to prebook their booster appointment a month before they are eligible. Everyone over 50 and all those most at risk from Covid-19 should get a booster six months after their second dose. Currently, someone can only book an appointment at six months.

The health secretary, Sajid Javid, said the plans would “accelerate the booster programme”. He urged people not to delay getting jabbed.

Dr Michelle Drage, chief executive of Londonwide LMCs, which represents GPs in 27 of the capital’s 32 boroughs, doubted that the change would increase uptake much. “It may make a small difference. But it doesn’t tackle the levels of vaccine hesitancy and denial that are prevalent in communities right now.”

But Ruth Rankine, director of primary care at the NHS Confederation, applauded the move. “Vaccination remains at the heart of our response to the pandemic,” she said. “Primary care sites will do everything they can to ensure that those eligible for vaccination get them without delay, and to do that well, the supply will need to match the volume and timing of appointments as they are booked.”

The latest evidence from the government scientific advisory panel shows that protection against symptomatic disease falls from 65%, up to three months after the second dose, to 45% six months after the second dose for the Oxford/AstraZeneca vaccine, and from 90% to 65% for the Pfizer/BioNTech vaccine.

The booster programme is designed to top up this waning immunity. Early results from Pfizer show that a booster after a primary schedule of the same vaccine restores protection to 95.6% against symptomatic infection.

The vaccines minister, Maggie Throup, said it was vital that people book their slots ahead of winter to protect themselves and their loved ones.

The NHS national medical director for England, Stephen Powis, said: “While this winter is undoubtedly going to be different, the most important thing you can do is come forward for both your Covid booster and flu jab as soon as possible – now with the added convenience of booking in advance – making it even easier to protect yourself and loves ones.”

The offer of a first and second Covid-19 vaccine is open to anyone who is eligible. Vaccines are available free of charge and from thousands of vaccine centres, GP practices and pharmacies.

There are more than 500 extra vaccination sites now in England compared with April this year, up from 1,697 to more than 2,500.

Vaccines are also available in schools for those aged 12-15, to offer the best possible protection this winter, as well as in more than 200 vaccine centres.