What is IHU? All you need to know about the latest Covid variant found in France

The new variant, possibly of Cameroonian origin, is believed to have infected at least 12 people in the country so far

PUBLISHED JAN 5, 2022

A vaccinated adult was was the first to be affected by the new variant, which has 46 mutations and 37 deletions (Jeff J Mitchell - Pool /Getty Images)

A new Covid variant detected by French researchers has been temporarily named 'IHU'. The variant, possibly of Cameroonian origin, from the lineage named B.1.640.2, is believed to have infected at least 12 people in the country so far. The information is available in a yet-to-be peer-reviewed study supported by the French Government.

The new variant has 46 mutations and 37 deletions. "For twelve SARS-CoV-positive patients living in the same geographical area of southeastern France, qPCR testing that screen for variant-associated mutations showed an atypical combination," said Philippe Colson, from IHU Mediterranee Infection, Marseille, France. Colson added that "it is too early to speculate on virological, epidemiological or clinical features of this IHU variant based on these 12 cases."

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The study says that the first patient was a vaccinated adult. The individual had returned to France from a trip to Cameroon in central Africa. He developed mild respiratory symptoms. Colson said that his nasopharyngeal sample collected mid-November 2021 "revealed an atypical combination that did not correspond to the pattern of the Delta variant involved in almost all SARS-CoV-2 infections at that time", and later also to Omicron.

Respiratory samples collected from seven other SARS-CoV-2-positive patients -- two adults and five children (below 15 years of age) -- who live in the same geographical area exhibited the same combination of mutations screened by qPCR. As recommended by French public health authorities, the respiratory samples from all these patients were sent to university hospital institute Mediterranee Infection for SARS-CoV-2 genome sequencing.

More tests prompted the identification of SARS-CoV-2 genotype. As per the analysis, 46 mutations and 37 deletions resulted in 30 amino acid substitutions and 12 deletions. As many as 14 amino acid substitutions and nine deletions are located in the spike protein. The amino acid substitutions include N501Y and E484K.

"This genotype pattern led to create a new Pangolin lineage named B.1.640.2, which is a phylogenetic sister group to the old B.1.640 lineage renamed B.1.640.1. Both lineages differ by 25 nucleotide substitutions and 33 deletions," the study said.

"The mutation set and phylogenetic position of the genomes obtained here indicate, based on our previous definition, a new variant we named 'IHU'," Colson said, adding that the data is "another example of the unpredictability of the emergence of SARS-CoV-2 variants".

"Overall , these observations show once again the unpredictability of the emergence of new SARS-CoV-2 variants and their introduction from abroad, and they exemplify the difficulty to control such introduction and subsequent spread," Colson said. "SARS-CoV-2 variants have become a major virological, epidemiological and clinical concern, particularly with regard to the risk of escape from vaccine-induced immunity. The emergence of the new variant warrants the increase of genomic surveillance of SARS-CoV-2," he added.