London: BA.4.6, a subvariant of the omicron COVID variant which has been quickly gaining traction in the US, is now confirmed to be spreading in the UK. The latest briefing document on COVID variants from the UK Health Security Agency (UKHSA) noted that during the week beginning August 14, BA.4.6 accounted for 3.3 per cent of samples in the UK. It has since grown to make up around 9 per cent of sequenced cases.
Similarly, according to the Centres for Disease Control and Prevention, BA.4.6 now accounts for more than 9 per cent of recent cases across the US. The variant has also been identified in several other countries around the world.
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So what do we know about BA.4.6, and should we be worried? Let’s take a look at the information we have so far.
BA.4.6 is a descendant of the BA.4 variant of omicron. BA.4 was first detected in January 2022 in South Africa and has since spread around the world alongside the BA.5 variant.
It is not entirely clear how BA.4.6 has emerged, but it’s possible it could be a recombinant variant. Recombination happens when two different variants of SARS-CoV-2 (the virus that causes COVID-19) infect the same person, at the same time.
While BA.4.6 will be similar to BA.4 in many ways, it carries a mutation to the spike protein, a protein on the surface of the virus which allows it to enter our cells.
This mutation, R346T, has been seen in other variants and is associated with immune evasion, meaning it helps the virus to escape antibodies acquired from vaccination and prior infection.
Severity, infectiousness and immune evasion Fortunately, omicron infections generally cause less serious illness, and we’ve seen fewer deaths with omicron than with earlier variants. We would expect this to apply to BA.4.6 too. Indeed, there have been no reports yet that this variant is causing more severe symptoms.
But we also know that omicron subvariants tend to be more transmissible than previous variants.
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BA.4.6 appears to be even better at evading the immune system than BA.5, the currently dominant variant. Although this information is based on a preprint (a study that is yet to be peer-reviewed), other emerging data supports this.
According to the UKHSA’s briefing, early estimates suggest BA.4.6 has a 6.55 per cent relative fitness advantage over BA.5 in England.
This indicates that BA.4.6 replicates more quickly in the early stages of infection and has a higher growth rate than BA.5.
The relative fitness advantage of BA.4.6 is considerably smaller than that of BA.5 over BA.2, which was 45 per cent to 55 per cent.
The University of Oxford has reported that people who had received three doses of Pfizer’s original COVID vaccine produce fewer antibodies in response to BA.4.6 than to BA.4 or BA.5. This is worrying because it suggests that COVID vaccines might be less effective against BA.4.6.
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The capacity of BA.4.6 to evade immunity may however be addressed to a degree by the new bivalent boosters, which target omicron specifically, alongside the original strain of SARS-CoV-2. Time will tell.
Meanwhile, one preprint study shows that BA.4.6 evades protection from Evusheld, an antibody therapy designed to protect people who are immuno-compromised and don’t respond as well to COVID vaccines.
Vaccination is key The emergence of BA.4.6 and other new variants is concerning. It shows the virus is still very much with us, and is mutating to find new ways to overcome our immune response from vaccination and previous infections.
We know people who have had COVID previously can contract the virus again, and this has been particularly true of omicron. In some cases, subsequent episodes can be worse.
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But vaccination continues to offer good protection against severe disease, and is still the best weapon we have to fight COVID. The recent approval of bivalent boosters is good news. Beyond this, developing multivalent coronavirus vaccines that target multiple variants could provide even more durable protection.
A recent study showed that a multivalent coronavirus vaccine administered through the nose elicited a strong immune response against the original strain of SARS-CoV-2, as well as two variants of concern, in mouse models.
Close monitoring of new variants including BA.4.6 is pressing, as they could lead to the next wave of COVID pandemic.
For the public, it will pay to stay cautious, and comply with any public health measures in place to prevent the spread of what remains a very contagious virus.
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(This story has not been edited by NDTV staff and is published from a syndicated feed.)
NDTV – Dettol have been working towards a clean and healthy India since 2014 via the Banega Swachh India initiative, which is helmed by Campaign Ambassador Amitabh Bachchan. The campaign aims to highlight the inter-dependency of humans and the environment, and of humans on one another with the focus on One Health, One Planet, One Future – Leaving No One Behind. It stresses on the need to take care of, and consider, everyone’s health in India – especially vulnerable communities – the LGBTQ population, indigenous people, India’s different tribes, ethnic and linguistic minorities, people with disabilities, migrants, geographically remote populations, gender and sexual minorities. In wake of the current COVID-19 pandemic, the need for WASH (Water, Sanitation and Hygiene) is reaffirmed as handwashing is one of the ways to prevent Coronavirus infection and other diseases. The campaign will continue to raise awareness on the same along with focussing on the importance of nutrition and healthcare for women and children, fight malnutrition, mental wellbeing, self care, science and health, adolescent health & gender awareness. Along with the health of people, the campaign has realised the need to also take care of the health of the eco-system. Our environment is fragile due to human activity, which is not only over-exploiting available resources, but also generating immense pollution as a result of using and extracting those resources. The imbalance has also led to immense biodiversity loss that has caused one of the biggest threats to human survival – climate change. It has now been described as a “code red for humanity.” The campaign will continue to cover issues like air pollution, waste management, plastic ban, manual scavenging and sanitation workers and menstrual hygiene. Banega Swasth India will also be taking forward the dream of Swasth Bharat, the campaign feels that only a Swachh or clean India where toilets are used and open defecation free (ODF) status achieved as part of the Swachh Bharat Abhiyan launched by Prime Minister Narendra Modi in 2014, can eradicate diseases like diahorrea and the country can become a Swasth or healthy India.