By ELIZ­A­BETH ME­LIMOPOU­LOS, Al Jazeera

(AL JAZEERA) — Health of­fi­cials and sci­en­tists are close­ly track­ing a new mu­ta­tion of the coro­n­avirus amid con­cerns that it could be more trans­mis­si­ble than the orig­i­nal strain.

A sub­vari­ant of the Delta vari­ant of the virus la­belled AY.4.2 has been de­tect­ed in dozens of coun­tries, with the vast ma­jor­i­ty of cas­es be­ing re­port­ed in the Unit­ed King­dom.

“An in­crease in AY. 4.2 se­quence sub­mis­sions has been ob­served since Ju­ly,” the World Health Or­ga­ni­za­tion (WHO) said in its week­ly epi­demi­o­log­i­cal up­date this week.

It said that 93 per­cent of AY.4.2 cas­es were re­port­ed in the UK, where the strain was grad­u­al­ly con­tribut­ing to a greater pro­por­tion of cas­es and ac­count­ed for about 5.9 per­cent of over­all Delta cas­es re­port­ed there in the week be­gin­ning Oc­to­ber 3.

“Epi­demi­o­log­i­cal and lab­o­ra­to­ry stud­ies are on­go­ing” to as­sess if there has been a change of trans­mis­si­bil­i­ty or a de­crease in the ef­fect of the an­ti­bod­ies to re­pel the virus, the Unit­ed Na­tions health agency added.

The UK’s Health Se­cu­ri­ty Agency (UKHSA) last week la­belled AY.4.2 as a “vari­ant un­der in­ves­ti­ga­tion,” but de­spite its spread, it has not yet been la­belled as a “vari­ant of con­cern”.

What is the new AY.4.2 strain?

The sub­vari­ant is an evo­lu­tion of the high­ly trans­mis­si­ble Delta vari­ant of the coro­n­avirus. Sci­en­tists have found three mu­ta­tions in­clud­ing two in the spike pro­tein, the part of the virus that al­lows it to bind to and in­vade the body’s cells.

The new strain has been found in at least 42 coun­tries, ac­cord­ing to a WHO epi­demi­o­log­i­cal up­date, in­clud­ing the UK, In­dia, Is­rael, the Unit­ed States and Rus­sia.

The sub­vari­ant, which some have la­belled as “Delta Plus,” con­tains changes that could give the virus sur­vival ad­van­tages over oth­er vari­ants.

Pre­vi­ous­ly, vari­ants have fu­elled new surges in coro­n­avirus cas­es. The Al­pha vari­ant spread wide­ly af­ter it was dis­cov­ered in the UK in late 2020, and the Delta vari­ant has be­come the dom­i­nant strain of the virus world­wide since it was dis­cov­ered in In­dia in late 2020.

How­ev­er, ex­perts have not­ed that AY.4.2 has not be­come the dom­i­nant strain in the coun­tries where it has been re­port­ed.

“Cur­rent­ly, the strain has been found in some oth­er coun­tries, but it is not be­com­ing pre­dom­i­nant,” Dr Rose­lyn Lemus-Mar­tin, who holds a PhD in mol­e­c­u­lar and cell bi­ol­o­gy from the Uni­ver­si­ty of Ox­ford, told Al Jazeera.

“It’s pos­si­ble that we see a sit­u­a­tion sim­i­lar to the Lamb­da strain … at the start, peo­ple were con­cerned but even­tu­al­ly its pres­ence was di­lut­ed in places like the US or the UK,” she added.

Ex­perts have al­so not­ed that sim­i­lar mu­ta­tions have been wit­nessed in oth­er vari­ants and oth­er lin­eages of the Delta vari­ant, with­out hav­ing a large ef­fect on the virus.

The Delta vari­ant re­mains “by far the most dom­i­nant vari­ant in terms of glob­al cir­cu­la­tion”, Maria Van Kerk­hove, the World Health Or­ga­ni­za­tion’s epi­demi­ol­o­gist, said at a pub­lic ses­sion in ear­ly Oc­to­ber.

“Delta is dom­i­nant, but Delta is evolv­ing,” she said, adding that the more the virus cir­cu­lates, the greater the chances it has to mu­tate.

Is AY.4.2 more trans­mis­si­ble than Delta?

It is still un­clear “whether it is more trans­mis­si­ble or whether it is more ca­pa­ble of evad­ing any im­mu­ni­ty that we have through the vac­ci­na­tion,” Dr Patrick Tang, the Di­vi­sion Chief of Pathol­o­gy Sci­ences at Sidra Med­i­cine in Qatar told Al Jazeera.

“We don’t have enough da­ta to point one way or an­oth­er.”

Ex­perts warned that the spread of the vari­ant could be the re­sult of a num­ber of fac­tors, in­clud­ing pub­lic health mea­sures set out by gov­ern­ments or ad­her­ence to those mea­sures.

“The mi­nor changes in the virus are al­most nev­er caus­ing an in­crease in trans­mis­sion. The in­creased trans­mis­sion … is re­al­ly an in­di­ca­tion of pub­lic health re­sponse or com­pli­ance to pub­lic health mea­sures,” he added.

Ac­cord­ing to Lemus-Mar­tin, it is not clear whether its spread in the UK is a re­sult of with bi­o­log­i­cal rea­sons or if it is linked to the “epi­demi­o­log­i­cal con­di­tions in the UK”.

“In the UK the cur­rent mea­sures against COVID-19 are very lax, prac­ti­cal­ly they are not fol­low­ing them any­more, and we don’t know if that might be the rea­son for the spread,” she added.