Matt Hancock has conceded he is unsure how many Britons will need to receive a Covid-19 vaccine before restrictions can be lifted.

The Health Secretary told MPs “help is on its way” in the battle with the virus following the decision to approve a jab from Pfizer and BioNTech.

But he added that while it is known the vaccine protects you as an individual, it is unclear what impact it has on reducing the transmission of Covid-19.

It is hoped rates of the virus will decrease as more vulnerable people are vaccinated thereby paving the way to lift restrictions, Mr Hancock explained.

His remarks came as he delivered a statement to the Commons to update MPs about the vaccine progress.

Replying to questions from shadow health secretary Jon Ashworth, Mr Hancock said: “He then asks about when we’ll get to lift restrictions, and of course I understand not only why he but almost everybody in the country wants to know the answer to this question – how many people do you have to vaccinate before you can start lifting the restrictions?

“The answer to that is while we know that the vaccine protects you as an individual with a 95% efficacy, we do not know the impact of the vaccine on reducing the transmission because of the problem of asymptomatic transmission – which has so bedevilled our response to this virus and made it so hard to tackle.

“Therefore we don’t know the answer to that question.

“What we will do is follow the same five indicators we were discussing at length yesterday, which are the indicators of the spread of the disease – we’ll look at the cases, the hospitalisations and, of course, the number of people who die with Covid.

“We would hope very much as we vaccinate more and more vulnerable people, we will see those rates come down and therefore we will be able to lift the restrictions. We will have to see how the vaccination programme impacts directly on the epidemic and then, of course, move as swiftly as we safely can to lift the restrictions that we all want to see gone.”

Labour’s Mr Ashworth earlier praised the vaccine news, adding: “I wonder if we should as a nation come together and applaud our scientists as well one evening.”

Vaccination, he said, saves lives, adding: “If it helps, I will stand alongside the Secretary of State, socially distanced of course, on any platform or in any TV studio to show that we are united cross-party in promoting vaccination.”

He also asked how many NHS staff the Health Secretary expects to be vaccinated by January.

Mr Hancock, in his reply, said: “While today brings more certainty, it doesn’t end all uncertainties – while we have 800,000 (doses) that have now passed the batch testing, the total number that will be manufactured over this time frame is not yet known because it’s all dependent on a manufacturing process which is complicated itself.”

SNP health spokeswoman Dr Philippa Whitford said: “As chair of the All-Party Group on Vaccination, I absolutely welcome the authorisation of the Pfizer vaccine and would echo (Mr Ashworth’s) call for a public health campaign to encourage uptake.

“It will naturally take some time before it’s widely available so we all still need to stick to the rules and ensure we can test, trace, isolate and support all those carrying the virus.”