WHO has tweeted an explainer on a recombinant of Delta AY.4 and Omicron BA.1
Coronavirus has been throwing new challenges everyday. Recently, the World Health Organisation (WHO) confirmed the possibility of recombinant viruses. Last week, the WHO had confirmed the emergence of a new recombinant virus which is a combination of the BA.1 and BA.2 Omicron strains.
On March 19, the WHO tweeted an explainer on a recombinant of Delta AY.4 and Omicron BA.1.
"Recombinants are expected as #SARSCoV2 is widespread among humans and many animal species now. Testing, surveillance (including ILI & SARI), sequencing & data sharing are still important to keep track of the pandemic & take early action when new variants emerge," WHO Chief Scientist, Soumya Swaminathan, tweeted on Sunday.
What is a recombinant virus?
A combination of the Omicron and Delta coronavirus variants is known as a recombinant, says Dr Maria Van Kherkhove, Infectious Disease Epidemiologist and COVID-19 Technical Lead-WHO. As per a research report, this has the spike and structural proteins from BA.1 and the remaining part of the genome from Delta.
WHO has warned against the emergence of recombinant viruses. Prior to this, it had also confirmed the emergence of a recombinant of BA.1 and BA.2 strains of Omicron. This recombinant was found in two passengers in Israel. This recombinant was detected through RT PCR method, the gold standard method of detecting coronavirus so far.
As per reports, the Alpha and Wuhan strain recombinant was the first.
How are recombinants different from original strains?
Ever since the outbreak of coronavirus induced COVID-19 infection, we have been dealing with the original strains of the virus along with its mutants. So far, out of a number of coronavirus variants, 5 have been tagged as variants of concern by the WHO. These 5 variants are responsible for infecting a massive population worldwide and have emerged one after the other causing severe and disastrous waves of COVID infection.
Recombinants have the genetic composition of both the strains from which they originate. In coronavirus context, more information on the genetic constituency is yet to be known.
What causes recombination in viruses?
Recombination occurs when at least two viral genomes co-infect the same host cell and exchange genetic segments. Recombination occurs between members of the same virus types.
There are different types of recombination in viruses: Homologous recombination, non-homologous recombination, and shuffling or reassortment.
How many recombinants of coronavirus have been detected so far?
So far, the WHO has talked about two recombinants: Deltacron and a recombination of BA.1 and BA.2 strains of Omicron.
Reports say, the first recombinant virus was that of Alpha strain and the Wuhan strain.
What is the effect of a recombinant virus?
Undoubtedly recombination expands the range of viruses by bringing in more new viruses. It aids the evolution of the virus, thus putting more challenges before the researchers and experts.
"Recombination is a widespread phenomenon in viruses and can have a major impact on their evolution. Indeed, recombination has been associated with the expansion of viral host ranges, the emergence of new viruses, the alteration of transmission vector specificities, increases in virulence and pathogenesis, the modification of tissue tropisms, the evasion of host immunity, and the evolution of resistance to antivirals," points out the research study.
Are recombinant viruses more severe than the ancestral strains?
As of now, nothing can be said. "Yes we are aware of this recombinant. This is a combination of Delta AY.4 and Omicron BA.1. It has been detected but there are very low levels of detection," says Dr Kerkhove and adds that " we have not seen any change in the epidemiology or severity regarding the recombinant. But there are various studies that are underway.
However, it is to be noted that the Delta and the Omicron variants of the coronavirus were so contagious that the healthcare management system had almost crippled during the infection waves caused by these two strains.
Read: Maharashtra on alert as Omicron BA.2 cases surges globally; know the symptoms of new variant
What is WHO’s response on recombinant viruses?
On the reason behind the emergence of the recombinants, Dr Kerkhove explains, "What happens when we allow the virus to circulate at such an intense level. The virus continues to evolve and more variants are expected. Recombinants are also expected… as we have been explaining for a very long time."
"We do expect to see recombinants. WHO has been aware of this. This is something on our radar and we are monitoring it,” she added.
Dr Kerkhove emphasizes on the need for testing, genome sequencing, proper geographic representation of genome sequencing across the world.