Health Secretary Matt Hancock said the “abundance of caution” displayed by regulators recommending under-30s are offered an alternative jab to Oxford/AstraZeneca should reassure the public.

Asked if he fears the move will provoke a drop off in the uptake, he told Sky News: “There’s no need of that. We’ve seen this incredible uptake of the vaccine in this country.

“What we’ve learned in the last 24 hours is that the rollout of the vaccine is working, we’ve seen that the safety system is working, because the regulators can spot even this extremely rare event – four in a million – and take necessary action to ensure the rollout is as safe as it possible can be.

“And we are seeing that the vaccine is working. It’s breaking the link between cases and deaths.”

He added: “The speed of the vaccination programme is not affected by the decisions yesterday. You can see and be reassured by the fact we’re taking an abundance of caution and we’re making sure we’re rolling this out in the safest way possible.”

“All three vaccines that are in use in the UK are safe and they’re safe at all ages, but there’s a preference for the under-30s, if they want to have the Pfizer or Moderna jab, then they can,” said Mr Hancock.

Health Secretary Matt Hancock said there is “more than enough” Pfizer and Moderna doses to cover the remaining 18-29 year olds.

He told Sky News: “There are 10.16 million people aged 18-29 in the UK, 1.6 million of them have already had their first jab.

“Anybody who’s had the jab should continue with the second jab because there’s no evidence of this affect after a second jab and we have more than enough Pfizer and Moderna vaccine to cover all of the remaining 8.5 million people aged between 18-29 if necessary.”

He insisted the UK remained “on track” to hit the target of all adults being offered the jab by the end of July.

The prevalence of coronavirus cases in England fell by around 60 per cent over the last month, with around 1 in 500 people on average still carrying the virus in March.

The latest React study, which monitors the spread of the virus in the community, has suggested there had been big falls in the southeast and London in March compared to the previous month.

However, researchers have said the latest figures suggest the decline in prevalence may be “levelling off”, reports Vincent Wood.

Modelling by University College London (UCL) suggests that Britain will pass the threshold for herd immunity by 12 April, which scientists described as “surprising”.

The UCL results estimate that the number of people who have protection against Covid-19 – through vaccination or previous infection – will hit 73.4 per cent on Monday.

It comes after the Office for National Statistics (ONS) published a study last week suggesting that in the week ending 14 March, more than half (54 per cent) of people in England already had Covid antibodies.

Professor Karl Fristen of UCL told The Telegraph: “The herd immunity estimates surprised me. However, they are unremarkable when one considers that over 50 per cent of adults have been vaccinated, around 42 per cent of people have now been exposed to the virus and about 10 per cent have pre-existing immunity.

“When factoring in the estimated efficiency of vaccination in terms of sterilising immunity, this – according to the model – means about 70 per cent of the population are immune.

“Based on contact rates at the beginning of the pandemic and estimated transmission risk, this is nearly at the herd immunity threshold.”

Ministers and health experts are urging the public to continue taking the Oxford/AstraZeneca Covid vaccine after UK regulators said there was a possible link between the jab and “extremely rare” blood clots.

Prime minister Boris Johnson said on Wednesday: “These vaccines are safe, they’ve saved many thousands of lives and people should come forward to get their jabs and we’ll make sure that they get the right jabs.”

Health secretary Matt Hancock tweeted that the findings by the Medicines and Healthcare products Regulatory Agency (MHRA) – which said the benefits of the jab still outweigh the risks overall – and the European Medicines Agency confirmed the AstraZeneca jab was “safe”.

It comes as the MHRA recommended that people under the age of 30 be offered the Pfizer, Moderna, or other vaccines that get approved as the vaccination rollout continues across the UIK.

MHRA’s chief executive Dr June Raine told a press conference that there was a “reasonably plausible” link between the AstraZeneca jab and blood clots, but stressed these were “extremely rare”.

She said: “Based on the current evidence, the benefits of the Covid-19 vaccine AstraZeneca against Covid-19 and its associated risks – hospitalisation and death – continues to outweigh the risks for the vast majority of people.

“Our review has reinforced that the risk of this rare suspected side effect remains extremely small.”

Good morning, and welcome to The Independent’s liveblog following the latest developments in the coronavirus pandemic.