A coronavirus vaccine is “unlikely” to be available before spring 2021, Patrick Vallance has said, as he warned ministers not to be tempted to “over-promise”. 

Speaking to MPs on Monday, the chief scientific adviser said the public, who face a winter of social distancing restrictions as the Covid-19 second wave gathers pace, need a “realistic picture” of how quickly the pandemic will end. 

It follows Boris Johnson and other ministers hinting there was a “chance” a vaccine could be ready by Christmas or New Year. 

Hearts also leapt when director-general of the World Health Organisation Tedros Adhanom Ghebreyesus claimed earlier this month “there is hope” and a vaccine “could be ready by the end of the year”. 

But Vallance decisively poured cold water on the idea such a vaccine would be available for widespread use in the UK. 

He told MPs: “I have been clear right from January I thought it unlikely a vaccine for any sort of widespread use in communities [would be available] before at least spring next year.” 

Vallance, one of the key figures advising government on the pandemic, also went further in his gloomy predictions.  

He added: “If you think about the previous history of vaccines, the average time of making a vaccine from scratch is over ten years and it has never been done before in under five years at the very quickest.

“We are in an extraordinary situation where at least eight vaccines that are in quite large clinical studies around the world […] so we will know I think we will know I think over the few months whether we have any vaccines that really protect and how long they protect for.” 

A vaccine being developed by the University of Oxford, in collaboration with the pharmaceutical giant Astra Zeneca, is among those in the final stages. 

Vallance also warned, however, that a vaccine may not stop the disease completely. 

“I think it is unlikely that we will end up with a truly sterilising vaccine that completely stops infection,” he said.

“It is likely that this disease will circulate and be endemic. My assessment – and I think that’s the view of many people – is that’s the likely outcome.

“Clearly as management becomes better, as you get vaccination that will decrease the chance of infection and the severity of the disease – or whatever the profiles of the vaccines are – this then starts to look more like annual flu than anything else and that may be the direction we end up going in.”

Health secretary Matt Hancock has suggested that the military could be brought in to distribute a vaccine. 

But Vallance said while “we will know that over the next few months” whether one of the projects had developed an effective vaccine a “big logistical challenge lies ahead” and ministers had to develop a “sensible vaccination strategy across the population”. 

He also suggested that ministers were overplaying how early a vaccine could be available, saying: “You might be able to tell from the way I have spoken very often that I do think we should not over-promise. 

“I think is is very important that we give a realistic picture of where things are.”

It comes as Johnson faces a chorus of demands, from Labour, the government’s own scientific experts and in public polling, to impose a circuit breaker lockdown as infection and hospitalisations rise across the country. 

Welsh first minister Mark Drakeford announced on Monday there would be a time-limited lockdown in Wales, but Cabinet Office minister Michael Gove said on Sunday England was not likely to do the same.  

Johnson has previously said that the most vulnerable would get priority in the UK when a vaccine was available. 

He said in an interview earlier this month: “Obviously, if and when we get a vaccine then the crucial thing would be to ensure that we have sufficient supplies in this country, that we’re able to make it in this country, distribute it fast in this country, and clearly the priority for a vaccine will be those who are the most vulnerable groups.”