Food, Global Health 2 min

COVID-19: A potential treatment for loss of smell

PRESS RELEASE - One of the most persistent and debilitating symptoms of COVID19 is anosmia or loss of smell. Researchers at INRAE and ENVA have discovered that a corticoid treatment could help restore the olfactory capacities affected by the viral infection. These results, published on 27 February in Brain, Behavior, and Immunity, are a major step forward in understanding and treating this symptom.

Published on 27 February 2024

illustration COVID-19: A potential treatment for loss of smell

COVID-19 is known to cause loss of smell in certain patients. While this symptom is generally temporary, approximately 10% of patients may suffer from it for 6 months or more.

Earlier research carried out by a team of researchers from INRAE and ENVA observed that the SARS-CoV-2 infected olfactory mucosa is invaded by immune cells leading to its destruction and prolonged inflammation. Based on these observations, the same team decided to assess the effectiveness of corticosteroids--known for their anti-inflammatory properties—in restoring the sense of smell[1].

Their results support the existence of a direct link between the loss of smell caused by the virus and a decrease in the olfactory neuron population in the nasal mucosa[2]. In addition, they show that early treatment with dexamethasone, a commonly used corticosteroid, improves the recovery of olfactory abilities in animals.

The improvement of the olfactory capacities is associated with a reduction of the immunity cells in the mucosa, and an increased level of regeneration of the olfactory neuron population. These results suggest that the corticosteroid treatments currently used—which have not been very successful in the treatment of prolonged anosmia—could be more effective if prescribed early, at the onset of symptoms of loss of smell.


[1] Financed by the ANR (CORAR) and the ANRS (UCRAH)

[2] The olfactory neurons found in the mucosa are in direct contact with the odours passing through the nose and are responsible for detecting odorous molecules.




Laetitia Merle-Nguyen, Ophélie Ando-Grard, Clara Bourgon, Audrey St Albin, Juliette Jacquelin, Bernard Klonjkowski, Sophie Le Poder, Nicolas Meunier, Early corticosteroid treatment enhances recovery from SARS-CoV-2 induced loss of smell in hamster. Brain, Behavior, and Immunity, 2024, ISSN 0889-159,

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Communication department EnvA

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Nicolas Meunier Virology and molecular immunology (VIM), INRAE-UVSQ



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Food, Global Health

A French nasal vaccine project against COVID-19 blocks all transmission of the virus – another step taken

PRESS RELEASE - The development of a protein vaccine candidate for nasal administration has taken another step. Led by the BioMAP research team, from the Infectiology and Public Health (ISP) joint research unit run by INRAE and the Université de Tours, this project, supported by the Ministry of Higher Education, Research and Innovation, and accompanied by the ANRS | Maladies infectieuses émergentes, is moving up a gear. As new pre-clinical results obtained with the Delta variant this winter demonstrate the robustness of the concept of this vaccine toward blocking the contagiousness of SARS-CoV-2, the French start-up LoValTech, labelled Deeptech by BPI France, has been created. To accelerate the development of the project and consolidate the investment announcements, this new company now holds an exclusive worldwide licence to exploit the patent on the vaccine, granted by the Université de Tours and INRAE. LoValTech main objective is to manage the project from the development phases of the vaccine formulation through the clinical trials leading to a market launch between ends of 2023, beginning of 2024. Surrounded by an ecosystem of academic, hospital and innovation partners, and subject to compliance with a tight schedule and sufficient external investment, this project should contribute to overcome the pandemic crisis.

20 January 2022