What we know about the signs of the Omicron BA.4 and BA.5 sub-variants

Covid-19 cases are rising quickly again.

According to official Government data109,908 people tested positive for the virus in England in the seven days up to 24 June – a 37 per cent increase on the week prior.

However, the real numbers are likely to be far higher, as the Government is only tracking positive tests logged on its website, and the provision of free tests has now ended.

The Zoe Covid studywhich has been collecting data throughout the pandemic, says there are currently around 285,000 new infections across the UK every day.

It predicts that about 3.1 million people currently have symptomatic Covid-19.

Daily symptomatic infections have risen by 150 per cent this month, and according to Zoe data are at the highest level they have been for all but three weeks of the pandemic.

Tim Spector, the King’s College London professor who runs the app, told I he expects cases will rise to “just under” 300,000 a day by the weekend and could well keep rising next week – although he said he can’t be sure.

The spike in cases has been driven by the Omicron sub-variants BA.4 and BA.5which have ousted BA.2 as the dominant strains in the UK.

Here is what you need to know about them.

What are the symptoms of BA.4 and BA.5?

There is currently no evidence to suggest that BA.4 and BA.5 cause different symptoms to previous Covid strains.

The NHS lists the following as recognized Covid-19 symptoms:

  • High temperature or shivering (chills) – a high temperature means you feel hot to touch on your chest or back (you do not need to measure your temperature)
  • New, continuous cough – this means coughing a lot for more than an hour, or three or more coughing episodes in 24 hours
  • Loss or change to your sense of smell or taste
  • shortness of breath
  • Feeling tired or exhausted
  • Aching body
  • Headache
  • sore throat
  • Blocked or runny nose
  • loss of appetite
  • Diarrhea
  • Feeling sick or being sick

What’s different about these variants?

BA.4 and BA.5 were first detected in South Africa in January and February 2022.

They are both sub-variants of Omicron, but have mutations that give them significant differences to BA.1 and BA.2, which caused earlier waves of infections.

The European Center for Disease Prevention and Control (ECDC) says BA.4 and BA.5 both contain the amino-acid substitutions L452R, F486V, and R493Q in the spike receptor binding domain, which earlier strains do not.

These changes give the variants a growth advantage over BA.1 and BA.2, which was the previously dominant strain in the UK.

“Preliminary studies suggest a significant change in antigenic properties of BA.4 and BA.5 compared to BA.1 and BA.2,” ECDC says.

Are these variants more dangerous?

Scientists have found these variants are more infectious and better at evading immunity than previous strains.

However, there is “currently no evidence” BA.4 and BA.5 cause more serious illness, the UK Health Security Agency has said.

UKHSA’s latest analysis suggests that BA.5 is growing 35.1 per cent faster than BA.2, while BA.4 is growing approximately 19.1 per cent faster.

This suggests that BA.5 is likely to become the dominant Covid-19 variant in the UK, it says.

Professor Susan Hopkins, chief medical advisor at UKHSA, said: “It is clear that the increasing prevalence of Omicron BA.4 and BA.5 are significantly increasing the case numbers we have observed in recent weeks. We have seen a rise in hospital admissions in line with community infections but vaccinations are continuing to keep ICU admissions and deaths at low levels.

“As prevalence increases, it’s more important than ever that we all remain alert, take precautions, and ensure that we’re up to date with Covid-19 vaccinations, which remain our best form of defense against the virus. It’s not too late to catch up if you’ve missed boosters, or even first doses so please take your recommended vaccines.”

Professor Lawrence Young, a virologist at the University of Warwick, said the recent rise in cases is worrying and “demonstrates that there’s no room for complacency as far as Covid is concerned”.

However, he added: “The good news is that where other countries have experienced significant waves of B.4 and BA.5, namely Portugal and South Africa, these waves have now peaked without a major increase in severe disease, principally due to the levels of vaccination in these populations.

“The hope is that this will be similar here and that we have reached the peak of infections.”

More from Health

Will the vaccines work against BA.4 and BA.5?

A UK study suggests vaccines give similar protection for BA.1, BA.2, BA.4 and BA.5.

It also found a previous BA.2 infection gives better protection against reinfection by BA.4 and BA.5 than a previous infection by BA.1, although in both cases that protection is weak.

This means people who have had Covid in the past few months will be better protected than those who had it in the weeks before or after Christmas – both because they are more likely to have had BA.2 and because their immunity has waned less.

UKHSA has said: “So far, vaccination means that the rise in cases is not translating to a rise in severe illness and deaths. UKHSA scientists are urging anyone who has not had all the vaccines they are eligible for to make sure that they get them as soon as possible.”

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