Emergence of ‘Recombinant’ SARS-CoV-2 from the Merging of Two Variants

by Lana Rose Mangi (Ikirara)

Early this February, researchers from Los Alamos National Laboratory in New Mexico had recently discovered the first possible coronavirus hybrid created by a recombination event between two mutated strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), one originated from the UK and the other from California, US. The preliminary findings have been disclosed in a virtual scientific conference by Dr. Bette Korber. However, this discovery has yet to be published and is currently being peer-reviewed. 

Recombination is a fundamental part of coronaviruses’ life cycle. In a study published in January, researchers have infected cells with coronaviruses and monitored all the genome copies they made and they found a lot of jumping on and off concluding that recombination is indeed part of the viruses’ existence.

How did this recombinant virus come to exist?

Recombination allows the genetic material of two closely related viruses to come together to form a novel recombinant hybrid. This event can occur when host cells are co-infected with two different variants at once. In this case, the B.1.1.7 variant from the United Kingdom and the B.1.429 from California, US, where both carry mutations on their spike proteins.

Inside the infected host cell, specific viral proteins move along the length of the virus’ RNA genome to make copies of it. These viral proteins are prone to slipping off of the RNA genome it is copying and may hop onto another genome. In this recombination event, there are two different SARS-CoV-2 variants inside the host cell, where the viral proteins have the tendency to jump from one to another variant genome thus creating a mutated hybrid of coronaviruses with a different or combined pathogenic properties.

What risks does this recombinant virus pose?

Although only a single genome out of thousands has been discovered, it still concerns experts and epidemiologists as this hybrid may pose a bigger threat to public health. From the combination of a highly transmissible B.1.1.7 and an antibody-resistant B.1.429, it is not surprising that this hybrid may get both worst traits from its parent's genomes. Dr. Korber said at the conference, “This kind of event could allow the virus to have coupled a more infectious virus with a more resistant virus.”

There is a high risk of co-infection with the aforementioned variants especially with the recent surge of COVID-19 cases in Los Angeles caused by two variants that may lead to the merging of their genomes by recombination. However, based on the preliminary findings from the laboratory, there is still no evidence that this hybrid is being transmitted among the people. Thus, it is still unclear whether it is really more deadly and infectious to humans than the ones that have been circulating in the population. 

Should we be worried about this?

While this discovery is concerning, it is not surprising and is actually expected by researchers during the surfacing of the pandemic, given that recombination is a natural evolutionary mechanism among coronaviruses. In fact, most scientists think that it is possible that a recombination event gave rise to the emergence of SARS-CoV-2 that could infect human cells. 

Although recombination among coronaviruses sounds like a bad thing given that the resulting hybrid may carry the worst possible traits, the habit of recombination these viruses have may also be a vulnerability that can be used against them. Aside from the fact that it could contribute to our understanding of the SARS-Cov-2 virus itself, we may develop drugs that specifically target the proteins involved in the recombination to destroy their ability to replicate and to infect other cells. Furthermore, it could help in the development of vaccines in order to prevent a future pandemic to happen.