Two million Britons will be invited to have their Covid-19 booster vaccine this week, and a senior health chief is urging people to take up the offer.
After the UK recorded its highest weekly number of coronavirus cases since July on Sunday, NHS medical director Professor Stephen Powis warned "winter is coming" and infections are rising.
The government again ruled out a move to its coronavirus Plan B - despite urgent calls to bring in measures to curb the spread of the virus - and instead told the public Christmas can be saved if people get their booster jab.
Plan B includes working from home guidance, the mandatory use of face masks and the use of vaccine passports at higher-risk venues and mass gatherings.
But Professor Adam Finn, of the Joint Committee of Vaccination and Immunisation (JCVI), has warned the vaccination programme will not be enough to bring current infection rates under control.
He said people need to be testing themselves, wearing masks and avoiding crowds in enclosed spaces in order to prevent “a real meltdown”.
Professor Peter Openshaw, of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), said Plan B measures "are sensible and not very disruptive", while vaccine passports have been accepted "very easily in most other western European countries".
“What we’re facing at the moment is unacceptable, we’ve got roughly one in 55 people infected, which is an astonishingly high rate compared to most other west European countries," he told BBC Radio 4's Today programme. “This is connected with the lack of clear messaging about sensible measures that we should all be taking in order to reduce the spread of infection.”
“It’s not problematic to give clear leadership about the use of face masks, and working at home if you can is also not particularly disruptive for many people," he added.
“Those measures are likely to lead to a pretty good reduction in the really unacceptable number of cases that we’ve got at the moment".
Modelling seen by the government predicts there will be a rapid fall in infections within weeks without bringing in Plan B, reports the Daily Telegraph.
Health Secretary Sajid Javid said last week that new cases could reach 100,000 a day, but Downing Street has insisted there is still spare capacity in the NHS and that Plan B will only be activated if it comes under “significant pressure”.
The government is sticking to Plan A for now and has launched a media blitz in recent days encouraging people to get a booster vaccine, as well as urging those not yet jabbed to do so.
Who is eligible for a Covid booster vaccine?
People aged 50 and over
People who live and work in care homes
Frontline health and social care workers
People aged 16 and over with a health condition that puts them at high risk of getting seriously ill from Covid
People aged 16 and over who are a main carer for someone at high risk from Covid, or who live with someone who is more likely to get infections (e.g. someone who has had a transplant, or is undergoing cancer treatment)
People who are pregnant and in one of the eligible groups can also get a booster dose
If you are not sure if you, or someone you live with, has a health condition that is considered high risk, the NHS's guidance can help.
How do you get a booster vaccine?
You will be offered a booster Covid dose at least six months after you had your second jab.
The NHS is inviting most people for their booster jabs but you do not need to wait to be contacted if you are a frontline health or social care worker and can book online and the allocated time has passed since your last dose.
Although you should be contacted about booking a booster, you do not have to wait for this to happen if you are eligible.
The NHS website says: “If you have not been contacted and it’s been six months and one week (190 days) since your second dose, please try to book your appointment using this service.”
NHS England said more than five million people have already been given a booster jab since they started to be rolled out last month.
One Sunday, it said more than 800,000 people had their booster in the past 72 hours.
Mr Javid said on Monday morning he is “leaning towards” mandatory vaccination for all NHS staff.
“There’s around 100,000 that are not (vaccinated in the NHS)... If they haven’t got vaccinated by now then there is an issue about patient safety and that’s something the Government will take very seriously.”
The health secretary declined to say when the move would come in to force, saying “it will take some time to get it through Parliament” and he would then want to give people time to come forward to get their jab.
Any Britons who receive a text, letter or email from the NHS inviting them for a booster jab is urged to take up the offer as soon as possible, with 7.5 million people already offered a third vaccine.
Listen to the latest episode of ITV News's Coronavirus: Everything You Need To Know podcast:
The NHS is following guidance that boosters should be delivered at least six months after the second dose, with current evidence suggesting this is the best time to increase immunity to Covid-19.
Messages will come from NHSvaccine and will include a link to the NHS website.
Currently around 10 million people in England are eligible for a booster, including health and care workers, those with underlying health conditions, and people aged 50 and over.
Prof Powis said: “Winter is coming and infection rates are rising and so it’s now really important that everyone receiving their invite for a booster vaccine from the NHS this week books in at one of the convenient vaccinations sites around the country offering this crucial, additional protection.
“Thanks to NHS staff, nine in 10 people have had a first dose, saving tens of thousands of lives, and now more than five million boosters have been delivered in the first month of the rollout.
“I would urge anyone receiving an invite this week to book in as soon as possible, the booster dose is proven to significantly increase protection against Covid and will provide vital protection this winter.”