Coronavirus has undergone several mutations in the last two years.
The Omicron variant of coronavirus has led to spike in the number of COVID-19 cases in some countries. Its BA.2 sub-lineage is now the globally dominate strain, present in nearly 94 per cent of all the samples tested.
But now, health experts are concerned about two new sub-variants of Omicron. These variants - BA.4 and BA.5 - were discovered in South Africa and are being monitored by the World Health organization (WHO). It is already tracking BA.1 and BA.2 - now globally dominant - as well as BA.1.1 and BA.3.
What are BA.4 and BA.5 variants?
According to Tulio de Oliviera, the Director of Centre for Epidemic Response and Innovation (CERI) in South Africa, BA.4 and BA.5 share a similar spike profile as BA.2, except for additional mutations. He has shared a Twitter thread on the emergence of the new sub-variants.
Oliviera said that one of the spike proteins in these new sub-variants was present in Delta, Kappa and Epsilon variants of coronavirus.
How fast do these sub-variants spread?
The WHO said that it started tracking BA-4 and BA.5 because of their "additional mutations that need to be further studied to understand their impact on immune escape potential".
The UK's Health Security Agency said last week that BA.4 had been found in South Africa, Denmark, Botswana, Scotland and England from January 10 to March 30.
All the BA.5 cases were in South Africa as of last week, but on Monday Botswana's health ministry said it had identified four cases of BA.4 and BA.5, all among people aged 30 to 50 who were fully vaccinated and experiencing mild symptoms.
What about the severity of BA.4 and BA.5?
According to Oliviera, there is no cause for alarm as no major spike in cases, admissions or deaths has been reported in South Africa.
“The complex Immunity landscape in South Africa, with high population immunity, is probably one of the main causes of the low infections, hospitalization, and deaths since the Delta and Omicron BA.1 wave,” the healthcare expert said in one of the tweets.
He also said that it is too early to understand how the mutations in these two sub-variants will impact on epidemiology.
How many cases of these two sub-variants have been found?
According to WHO, only a few dozen cases of BA.4 and BA.5 have been reported to the global GISAID database.
How to protect ourselves from these new sub-lineages?
Oliviera has said that vaccination is the key to protect against severe disease, hospitalisation and death from all known variants.
Apart from that, following COVID protocols like wearing masks, maintaining social distance and washing hands regularly will also help in staying safe.