Hybrid versions of the coronavirus that combine genes from the Delta and Omicron variants - dubbed "Deltacron" - have been identified in at least 17 patients in the United States and Europe, researchers said.
Because there have been so few confirmed cases, it is too soon to know whether Deltacron infections will be very transmissible or cause severe disease, said Philippe Colson of IHU Mediterranee Infection in Marseille, France, lead author of a report posted on medRxiv ahead of peer review.
His team described three patients in France infected with a version of SARS-CoV-2 that combines the spike protein from an Omicron variant with the "body" of a Delta variant.
Another two unrelated Deltacron infections have been identified in the United States, according to an unpublished report by genetics research company Helix that has been submitted to medRxiv and seen by Reuters.
On virus research bulletin boards, other teams have reported an additional 12 Deltacron infections in Europe since January - all with an Omicron spike and a Delta body.
Genetic recombinations of human coronaviruses have been known to happen when two variants infect the same host cell.
"During the SARS-CoV-2 pandemic, two or more variants have co-circulated during same periods of time and in same geographical areas... This created opportunities for recombination between these two variants," said Colson.
He added that his team has designed a PCR test that "can quickly test positive samples for the presence of this... virus."
