Delta-Omicron Hybrid, No More a Lab Error

Source: Freepik

Scientists have confirmed the presence of a new COVID-19 variant that is a hybrid of the Delta and Omicron virus.

Earlier this year, scientists at the University of Cyprus reported the discovery of the ‘deltacron‘ virus. Led by Dr. Leondios Kostrikis, the team uploaded 25 genomic sequences, containing elements of both Delta and Omicron, to the international database. According to Dr. Kostrikis, his team had discovered Omicron-like genetic signatures within the spike protein of the Delta variant. However, the scientific community was quick to blame it on lab contamination. Now, just two months later, scientists have confirmed that a Delta-Omicron hybrid does really exist. The team published their findings in a preprint study available on bioRxiv.

Given the divergence of Delta and Omicron genomes, as well as Omicron’s known immune escape properties, a Delta-Omicron recombinant strain could alter the landscape of vaccine and therapeutic efficacy.

study author

Through the CDC’s national genomic surveillance, the team identified nine candidate recombinant sequences of SARS-CoV-2 containing both Delta and Omicron mutations. To rule out lab contamination or sequencing error, the team further sequenced the recombinants using Illumina and PacBio, along with Nanopore sequencing. Thus, confirming that the new coronavirus recombinant contains a Spike protein with characteristics from both Delta and Omicron. Fortunately, the study authors did not find any extra amino acid mutations in the receptor-binding site compared to the Omicron variant.

Although multiple countries have reported cases of the Delta-Omicron hybrid, study authors believe the cases are spreading at a very low rate. Moreover, the majority of these cases occurred in the United States.

It is important to note that recombinants are a common result of viruses mutating. Their emergence does not point to increased virulence or decreased vaccine efficacy. However, it is critical that these hybrids are routinely monitored to contain the spread of the viruses.


Lacek, Kristine A., et al. “Identification of a Novel SARS-COV-2 Delta-Omicron Recombinant Virus in the United States.” 2022, doi:10.1101/2022.03.19.484981.


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