It comes as coronavirus hospital cases in the UK are rising again. Scientists from L’Institut Pasteur in Paris published a report this week on three cases of a variant with the spike protein of Omicron and a “backbone” derived from Delta.
Several other countries have also detected hybrids, although it is not clear whether they are the same ones or slightly different combinations.
Such variants are created when strains exchange genetic material, usually after one person becomes infected with both at the same time.
The World Health Organisation is keeping watch on a Deltacron variant. Its Covid-19 lead Maria Van Kerkhove said: “It’s a combination of Delta AY.4 and Omicron BA.1.
Low “It has been detected in France, the Netherlands, Denmark, but there are very low levels of detection.”
She said there was no sign it was more severe and the emergence of such strains was expected “given the intense amount of circulation that we saw with both Omicron and Delta”.
A report from the UK Health Security Agency last month revealed it had detected 32 cases of a suspected combination variant containing both Delta and Omicronlike mutations.
A source said: “It’s not displaying a level of growth that we think is concerning.”
Professor Paul Hunter, an expert in medicine at the University of East Anglia, said: “In theory, our existing immunity from either vaccine or prior infection should mean this variant won’t become a major threat. But we need to monitor this to check whether Deltacron behaves as expected.”
A further 71,259 Covid-19 cases and 142 deaths within 28 days of a positive test were reported in the UK yesterday. The Health Security Agency’s weekly report yesterday confirmed hospital admissions had begun to rise.
Chief medical adviser Dr Susan Hopkins said: “Covid-19 is still circulating at high levels due to the high transmissibility of circulating variants and increases in social mixing. While rates of severe disease and death remain low, hospital admissions have risen.”