The omicron variant of Covid-19 is “probably the most significant threat we’ve had since the start of the pandemic” and could place the NHS in “serious peril”, the head of the UK Health Security Agency Jenny Harries has warned MPs.
Dr Jenny Harries told a parliamentary committee that “quite staggering” numbers of infections can be expected in the coming days due to the highly contagious nature of the new strain.
And she warned that the speed of spread was accelerating, with infections now doubling in less than two days in most parts of the UK, compared to an estimated four or five days when the threat first emerged.
The multiple variations seen in the omicron virus means it “runs the risk of evading our natural and/or vaccine immunity”, warned the UKHSA chief executive.
The strain – first detected in South Africa – could have “very significant impact on our health services”, she said.
Dr Harries was speaking a day after chief medical officer Prof Chris Whitty told Boris Johnson’s cabinet that hospitalisations from omicron can be expected to increase “significantly” over the Christmas period.
With the UKHSA estimating daily infections at 200,000 on Monday this week, Dr Harries’ estimate of a doubling time of less than two days suggests that more than a million Britons a day could be catching the virus by the weekend, with millions infected by Christmas Day.
But she said it was too early to say whether high infection rates will translate into hospitalisations, severe illness and death.
Dr Harries told the House of Commons Transport Committee: “I’m sure … the numbers that we see on data over the next few days will be quite staggering compared to the rate of growth that we’ve seen in cases for previous variants.
“The real potential risk here – and I would underline that because we are still learning a lot about the variant – is in relation to its severity, clinical severity, and therefore whether those cases turn into severe disease, hospitalisations and deaths.
“We’re still at too early a stage for that, in fact the world probably is still at too early a stage to be clear.”
But she said it was clear that protection against infection was “much reduced” from two doses of vaccine and even with a booster jab was lower than had been the case with the earlier delta wave.
“We have early studies looking at immune serum from patients who’ve been ill and been vaccinated, to see that two doses of vaccine against symptomatic infection – so we don’t know yet about severe disease but about symptomatic infection – is much reduced,” she told MPs.
“We do know that the booster dose will push that right back up but it still comes back to a level below that that we’ve had with the booster effect for delta, our previous wave.”
Dr Harries said that the speed of the spread of omicron was much faster than the original coronavirus in the spring of 2020 or the later alpha and delta variants, meaning that large numbers of people are becoming infected before scientists have a clear idea of the likely outcome.
“The difficulty is the growth of this virus,” she said. “It has a doubling time which is shortening … it’s doubling faster, growing faster.
“In most regions in the UK it is now under two days. When it started we were estimating about four or five.”
While infection rates were particularly high in hotspot London and were rising fast on Tuesday in Manchester, the UKHSA was now “very sure there are levels growing across most communities in the UK now, although there is quite a lot of regional variation still”, she said.
Dr Harries’ appearance before the committee came as 11 countries in southern and western Africa were removed from the UK’s travel red list, in a sign that ministers accept that omicron is here in such quantities that there is no longer any point trying to keep it out.
She told MPs that travel restrictions played an important role, “particularly when we can foresee a very large wave of omicron coming through and our health services potentially being in serious peril”.
But she said the curbs “have a time and place” and it was important to free countries from restrictions as soon as it becomes clear they no longer serve a purpose.
“Very early restrictions were placed on countries where we had good evidence of high rates of omicron at a time where we had low knowledge of rates in the UK, as a delaying tactic,” she explained.
“That gives us time to prepare, to understand, to boost particularly our population, but actually it’s really important that where there isn’t a benefit, countries are clearly freed from those restrictions.
“At the moment the rate of growth in the UK … is now significant, and the benefit of those border controls against particular countries is reduced.
“However, because we now have widespread global cases of omicron there is still value in preventing that variant or other cases coming into the country when we don’t need it to be there, not least because we don’t want hospitals to be under any increased pressure than they are currently.”
MPs heard that there have been “unprecedentedly high rates” of positive Covid cases among travellers quarantined from the red list countries, including South Africa and Nigeria.
UKHSA official Jonathan Mogford told the committee: “The latest figures are suggesting that nearly 5 per cent of people in the hotels are positive.”
Of those, “at least 1 per cent are omicron-positive but probably as much as 3 per cent”.
With around 5,000 passengers staying in quarantine hotels during the latest round of restrictions, Mr Mogford’s figures suggest around 250 of them were infected with Covid-19, including 50-150 with omicron.
