In evidence to MPs on Wednesday, he urged the public to stick with current social distancing and restrictions but warned it would be “disastrous” to abandon them until the spring.
Whitty said that even with the rollout of vaccines, there would probably only be a “gradual retreat” from current tight public health curbs, suggesting it may be next summer until life will return to a semblance of normal for many people.
Chief scientific adviser Patrick Vallance said the timing of when to relax restrictions would be “a science-informed political decision”, adding the virus would still be in circulation even once the most vulnerable were vaccinated.
Fears that there may have to be a third national lockdown after Christmas have been heightened in recent days, amid worries that relaxation for the festive period could add to rising cases seen in London and the south east.
The warnings came as figures released on Wednesday show another 533 people were reported to have died after testing positive for Covid-19. It brings the total number of deaths in the UK to 62,566.
Meanwhile, another 16,578 coronavirus infections were also reported in the UK.
On Tuesday, health secretary Matt Hancock also revealed he was concerned about case numbers rising. And in Wales hospitalisations have soared in recent weeks since the end of its “firebreak”.
Appearing before a joint session of the Commons science and health select committees, Whitty stressed just how worried he and other scientists were.
“We’re heading into spring of 2021 in much better shape than we were three or four months ago,” he said.
“The first response is to say, ‘Well that’s it, it’s done.’ That would be disastrous because then [the virus] would come back again incredibly quickly, and we’re all very nervous about January and February, which is the highest risk period for the NHS in particular, March as well.”
Labour MP Zara Sultana asked: “In a few months will we be looking at Christmas like some are looking at the chancellor’s Eat Out To Help Out, saying that this has contributed to a significant rise in transmission and more deaths?”
Vallance replied: “We’re clear that the increased contacts over Christmas are likely to lead to an increase in numbers. I think it is likely that we will see an increase in numbers.
“The flip side to that is it’s a period when schools aren’t together so there may be a decrease as a result of that, but overall I think you’d expect there to be an increase in numbers.”
Vallance added that the relaxation of the rules from December 23 to 28, which allows “bubbles” from three different households, should be interpreted carefully.
“If you’re going to do ‘three households’, it may just literally mean parents and two children because they are in different households, that’s what it means. It doesn’t mean ‘three great big households’.
“And I think we need to make sure that where possible we do things outdoors, that we pay attention to things like ventilation in the household, keeping windows open, make sure that we obey the sort of basic rules around hand hygiene, masks and so on where appropriate.”
Whitty added: “I think we should basically view the next three months as a period at risk of which the festive season over Christmas is one of the risks.”
“The natural tendency is always psychologically to think it’s strangers who are the bigger risk. Actually when it comes to infections, it’s your family, it’s your friends, it’s your workmates who are your biggest risk.
“And that’s the group we all have to protect, ourselves from them, them from us, and by protecting ourselves protect others we come into contact with. And people have got to think about that when they think through their actions over the Christmas period.”
Whitty also said that even if 20 million of the UK’s most vulnerable people were vaccinated by the spring, the dangers of the virus would still be real for younger people.
“If you only were to vaccinate those 20 million people, the numbers are rough but for the sake of argument, you are still going to have a lot of people who are susceptible.
“That will not produce population immunity even if it prevents transmission. So what that will do is substantially reduce mortality, significantly reduce the impact on the NHS, but it will still leave a lot of people who could become ill with this, and could in some cases have serious outcomes.”
Vallance was also at pains to stress that the vaccine progress should not be an excuse for the public to drop their guard.
“The biggest risk we face now is everyone thinks this is all over – and it isn’t all over. We’re a long way off yet knowing how we can move it to the rest of the population, that’s dependent upon things like does the AZ (AstraZeneca/Oxford) vaccine get approved.
“It’s not the time to suddenly say we relax everything and, if that happens, we will have a big surge.”
Whitty added: “I want to be very clear: for the next three months we will not have sufficient protection. So the idea we can suddenly stop now because the vaccine’s here, would be really premature.
“It’s like someone giving up a marathon race at mile 16, it would be absolutely the wrong thing to do. But there will come a point where the choice about exactly when to start ramping down, how fast and which, needs to be made and that is fundamentally a science-informed political decision.”
The chief medical officer also revealed that with the Moderna vaccine due in the UK in 2021 “we expect, probably by the middle of the year, to have a portfolio of three or four vaccines which we can actually use”.
Both advisers said that the government had a duty to counter misinformation about vaccines, but Whitty said that there was a difference between vaccine-hesitant members of the public and a minority of hardline anti-vaxxers.
“There is a very small group of people who got very weird views about vaccines. In a sense, they’re not worth worrying about in public communication terms because no one, nothing will persuade them that this is the right thing to do. And that’s their right as competent adults to make those choices.
“There’s a lot of people though who actually have quite legitimate questions of any vaccine and any medical treatment, vaccines are no different to that.” Giving clear information about risk, impact and side effects of vaccines was crucial, he added.
Whitty said that at some point parliament will have to assess what is “appropriate to tolerate” from Covid, before allowing widespread relaxation of restrictions.
“Just as we accept that in an average year 7,000 people die of flu, and in a bad flu year, 20,000 people die of flu. We accept that as that is what happens biologically.
“At a certain point you say, ‘actually, the risk is now low enough that we can largely do away with certainly the most onerous things that we have to deal with’.”
“This will be a kind of gradual retreat from that, but it is a de-risking process rather than it’s just going to go away.”
With many Tory MPs demanding that Boris Johnson either reduce their local curbs or create smaller tiered areas, Whitty said that was a political decision but made clear there were health risks.
“If you make it too small, you’re asking for trouble because if you have a very small area that’s got low rates surrounded by an area of high rates, we’ve tried that experiment several times and it always ends up the same way, which is the small area with a low rate gets a high rate,” he said.
Vallance added that tougher restrictions were the ones that the public most clearly understood and followed: “We obviously don’t design the tier system, that’s a policy choice, but we try and give behavioural insights into what the impact will be.
“One of the things that ONS (Office for National Statistics) told us recently is that adherence is much greater in tier 3 than it was in lower tiers because people understood things better.”
In a wide-ranging evidence session on “lessons learned” from the pandemic, Whitty also revealed that the way Black and minority ethnic groups had been let down by the healthcare system was a key lesson.
“One thing which I think we really, really need to look at again is, I don’t think they got our messaging to some of the ethnic minority British groups right early on, and indeed some other smaller groups,” he said.
“We just didn’t actually have a clear campaign in those areas. And I think that is something which we need to look at fairly self-critically and work out how we could do that better next time round.”
He revealed that although the first wave of the pandemic had a disproportionate impact on Black and south Asian communities, the second wave had shown a “very large impact” on Pakistani communities.
Vallance also stressed that the government’s decisions on imposing a 10pm curfew for pubs before lockdown, a decision since amended, was not based on direct scientific evidence.
“There’s no really hard evidence on curfew times…it’s not something you can model with a degree of accuracy and say, a particular time will give you a particular result.”