A spike in Covid cases has been driven by a sub-lineage of the Omicron variant known as BA.2 or “Stealth Omicron”. Infection cases are on the rise particularly in South Africa and the US. What are the symptoms of this new variant and what does that mean for the UK?
BA.4 and BA.5 are both offshoots of the original Omicron variant and are two new Omicron variants sweeping South Africa.
In January, Omicron gave rise to a lineage of the virus with even more mutations, which included BA.4 and BA. 5.
These variants have also been discovered in the USA and are likely able to evade vaccines and natural immunity from previous infections, warned experts.
BA.4 and BA.5 appear to be more infectious than BA.2, also known as “stealth Omicron,” which was more infectious than the original Omicron, BA.1, Bloomberg reported, citing South African Covid expert Tulio de Oliveira, the head of the institutes at the universities of KwaZulu-Natal and Stellenbosch.
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Emerging data show that in unvaccinated people, BA.4 and BA.5 evade the natural defences produced from an Omicron infection.
The two new subvariants spread more quickly than BA.2, which itself was more contagious than the original Omicron variant.
Cases are surging in South Africa despite the fact that almost all South Africans have been vaccinated or had Covid.
The rising cases could be signalling that these strains are more likely to be capable of evading the body’s defences.
Scientists are still studying whether these new variants create more severe illness.
As of 24 January 2022 – the last available data figures – 1,072 genomically confirmed cases of BA.2 have been identified in England, according to the UK Health Security Agency (UKHSA).
The variant has also been reported in 40 countries, with Denmark seeing the biggest rise in BA.2 cases, although experts warn the new strain is on its way to overtaking the BA.1 strain in the UK.
Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said: “Early indicators suggest that the vaccines will provide similar levels of protection as we have seen for Omicron, so this is good news.
“Whether or not it causes more severe disease will become apparent as more data is collected.”
Doctor Julian Tang, Honorary Associate Professor/Clinical Virologist, Respiratory Sciences, University of Leicester, added: “Again, as the Omicron variant adapts further to this well-vaccinated human population, we may see more vaccine-escape capable variants arising.
“With higher viral loads and increased transmissibility this could lead to more infections/reinfections as vaccine immunity wanes over time – in a more well-mixed population.