A subvariant of Omicron that is growing quickly in Britain is not more vaccine-resistant than its ancestor strain, reassuring real-world data shows.
UK health officials said booster jabs may even offer slightly better protection against BA.2, which is believed to be more infectious than Omicron.
The subvariant makes up at least one in 125 new cases in England and it is outcompeting the original Omicron in some corners of Europe.
There were fears it may be able to slip past vaccine immunity more easily than Omicron, which would explain its evolutionary edge.
But an analysis by the UK Health Security Agency found two and three vaccine doses work just as well against both strains.
A booster was found to give 70 per cent protection against symptomatic infection from BA.2, compared to 63 per cent with the original Omicron.
Waning immunity from two doses only offers 13 per cent protection against the new subvariant, slightly more than the 9 per cent for its parent variant.
Immunity against severe disease is expected to be even higher but it takes several weeks for enough people to fall ill with a new strain to accrue the data.
It came as Sajid Javid, the Health Secretary, said it was the ‘professional duty’ of every NHS worker to get vaccinated ahead of new rules coming in next week.
Frontline staff must have their first jabs by February 3 to make sure they are double-vaccinated by April 1 or they will be sacked or deployed into backroom roles.
Meanwhile, separate official figures showed pregnant women who get vaccinated are not at a higher risk of complications, allaying long held concerns about jab safety in expectant mothers.
A booster was found to give 70 per cent protection against symptomatic infection from BA.2, compared to 63 per cent with the original Omicron. Waning immunity from two doses only offers 13 per cent protection against the new subvariant, slightly more than the 9 per cent for its parent variant
The above shows the number of BA.2 lineages detected by the Sanger Institute — one of the UK’s largest Covid surveillance centres — over the week to January 8 (left) and January 15 (right) broken down by local authority
Pictured above is the data from the Sanger Institute — one of the largest Covid surveillance centres in the UK — which shows BA.2 has now outpaced Delta
A booster jab was shown to be 88 per cent effective at preventing people ending up in hospital with the original Omicron.
Two doses initially give 72 per cent protection, although after six months that protection fades to 52 per cent.
Doctors and nurses have a ‘professional duty’ to get vaccinated, Health Secretary says
Doctors and nurses have a ‘professional duty’ to get vaccinated, the Health Secretary said today.
Asked about compulsory vaccines for NHS staff, Sajid Javid warned the rule was put in place to protect the employees and the ‘people that they look after every day’.
All health care workers must have received their first jab by February 3 — a week from today — to hit the deadline for being double-vaccinated in April.
Almost 100,000 people have come forward for their first dose since the policy was announced, Mr Javid said.
But there is still a group of 70 to 80,000 who have not come forward.
Mr Javid said: ‘I would just say that it is the professional duty of every health care worker or social care worker to get vaccinated to not only protect themselves, but most of all to protect the people that they look after every day.’
Mr Javid suggested at a committee appearance earlier this week that the rule could come ‘under review’ because of the spread of Omicron.
Pressed on this today, he said: ‘We’re reflecting on it because we do have to accept that the virus has changed.
‘It’s moved from Delta to Omicron, and I’ve been very open about that reflection, but it is still absolutely right that people that are working in the NHS, working in social care, carry out their professional duty, which is to do all that they can to put patient safety first, and that means getting vaccinated.’
Just a few hundred cases of BA.2 have been detected in the UK so far, but the number of people testing positive for the subvariant has quadrupled in the last week.
Data from the UK’s largest Covid surveillance lab shows BA.2 was behind 0.8 per cent of all positive samples in the seven days to January 15 — up from 0.2 per cent the week prior.
It suggests around one in 125 people who tested positive for Covid in this period had the new subvariant.
UKHSA analysis looked at infections with the two versions of Omicron over the four weeks to January 21.
Dr Mary Ramsay, immunisation head at the UKHSA, said: ‘The evidence is clear — the vaccine helps to protect us all against the effects of Covid and the booster is offering high levels of protection from hospitalisation and death in the most vulnerable members of our society.
‘The pandemic is not over yet and the vaccine is the best way to increase your protection against the serious consequences of this virus.’
Mr Javid said today it was the ‘professional duty’ of doctors and nurses to get the vaccine.
All NHS staff will need to have got their first does by February 3 — a week from today — in order to hit the April vaccination deadline.
Sajid Javid said almost 100,000 people had come forward for their jabs since the jabs were made compulsory.
But another 70 to 80,000 employees were still to come forward.
He told broadcasters today: ‘I would just say that it is the professional duty of every health care worker or social care worker to get vaccinated to not only protect themselves, but most of all to protect the people that they look after every day.’
Separate analysis from the UKHSA published today revealed how pregnant women who get vaccinated are not at a higher risk of complications compared to the unjabbed.
They had a similar rate of stillbirths, low birth weight and premature birth to their unvaccinated counterparts, figures showed.
Additionally of the 235 expectant mothers who were admitted to intensive care up to September last year, none had been given both jabs.
Dr Gayathri Amirthalingam, an epidemiologist at the UKHSA, said: ‘There is growing evidence indicating that if you are pregnant, you are at increased risk of serious illness from Covid, especially in late pregnancy.
‘Our ongoing monitoring of the vaccine programme continues to provide reassuring evidence on the safety of Covid vaccines in pregnant women.
‘I would urge all pregnant women to come forward and get their vaccine without delay. This is the best way to protect you and your baby.’
Health Secretary Sajid Javid (pictured today visiting a vaccine centre in London) has said doctors and nurses have a ‘professional duty’ to get their jabs
Pregnant women are not at higher risk of complications if they get vaccinated, UKHSA analysis shows
Pregnant women are not at higher risk of complications if they get the Covid vaccine, analysis suggests.
UKHSA scientists looked at the rates of stillbirths, low birth weight and premature births in vaccinated and unvaccinated expectant mothers.
But there was no difference shown between the two groups.
And out of the 235 pregnant women admitted to intensive care up to September last year, none had been given two doses.
Dr Gayathri Amirthalingam, an epidemiologist at the agency, described the data as ‘reassuring’ that jabs were safe for pregnant women.
‘I would urge all pregnant women to come forward and get their vaccine without delay,’ she said.
‘This is the best way to protect you and your baby.’
Figures showed vaccinated women had a similar rate of stillbirths compared to the unvaccinated (3.6 stillbirths per 1,000 births among vaccinated women compared to 3.9 per 1,000 in un-vaccinated).
This was also the case for low birth rate infants (5.01 per cent in vaccinated women compared to 5.33 per cent in vaccinated) and premature births (5.97 per cent in vaccinated women compared to 5.88 per cent in unvaccinated women).
Unlike the original Omicron, BA.2 infections can only be confirmed through lab analysis rather than a PCR, which has made tracking its spread more difficult and seen it nicknamed a ‘stealth’ variant.
Scientists believe BA.2 may have evolved to be slightly more transmissible than Omicron and could slowly become the UK’s dominant Covid virus.
There are already signs BA.2 outstripping its ancestral strain in Denmark, where it now makes up 45 per cent of all cases.
The Scandinavian nation’s daily cases have nearly doubled in a fortnight, despite having similar restrictions to the UK and being hit by Omicron at roughly the same time.
BA.2 differs from the original Omicron strain by around 20 mutations, scientists say, although only a few of these could make it better at evading vaccine-induced immunity.
But it still carries the changes that made Omicron more transmissible — and milder — than previous strains, but it is harder to detect.
The original strain has a specific alteration — known as an ‘S’ gene dropout — which meant it could be detected through PCR tests without the need for lab analysis.
But this does not appear to be the case with BA.2.
It doesn’t mean that BA.2 is undetectable by PCR, but samples will need to be sent for further analysis to confirm it is the subvariant.
It is likely that anyone who has already caught Omicron has strong protection against this variant.
But scientists in Denmark are investigating a handful of cases where someone who previously had Omicron later caught BA.2.
Professor Francois Balloux, a geneticist at University College London, said it was difficult to know whether Denmark’s spiralling cases were fuelled by BA.2 or if it had just ‘surfed’ the Omicron wave of infections.
He added to MailOnline: ‘The high prevalence in Denmark might stem from their low rate of hybrid immunity (which is vaccines plus previous infection).’
Professor Balloux said it would ‘come as a surprise’ if BA.2 triggered another wave of cases in the UK.