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2022, Number 3-4

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MEDICC Review 2022; 24 (3-4)

A Shift in SARS-CoV-2 Omicron Variant´s Entry Pathway Might Explain Different Clinical Outcomes

Machado-Curbelo C, Gutiérrez-Gil J, González-Quevedo A

Language: Spanish
References: 26
Page: 68-71
PDF size: 177.52 Kb.


ABSTRACT

Globally, SARS CoV-2 omicron variant has led to a notable increase of COVID-19 diagnoses, although with less severe clinical manifestations and decreased hospitalizations. The omicron wave swelled faster than previous waves, completely displacing the delta variant within weeks, and creating worldwide concern about fi nal, successful pandemic control. Some authors contend that symptoms associated to omicron diff er from ‘traditional’ symptoms and more closely resemble those of the common cold. One major COVID-19 symptom frequent with other variants— loss of taste and smell—is rarely present with omicron. This may be of interest, since it has also been suggested that direct SARS-CoV-2 invasion into the brainstem through the olfactory nerves by transsynaptic pathways could provide one explanation for the acute respiratory distress syndrome refractory to treatment. Brainstem infection by SARS-CoV-2 can severely damage the respiratory center, triggering functional deviations that aff ect involuntary respiration, leading to acute respiratory distress syndrome refractory to treatment, the main cause of death in COVID-19 patients. A shift in the omicron SARSCoV- 2 entry pathway from cell-surface fusion, triggered by TMPRSS2, to cathepsin-dependent fusion within the endosome, may aff ect transmission, cellular tropism and pathogenesis. Therefore, we can hypothesize that this entrance modifi cation may impact transmission from the olfactory nerve to the brainstem through transsynaptic pathways. A decrement of the virus’s direct invasion into the brainstem could diminish respiratory center dysfunction, reducing acute respiratory distress syndrome and the need for mechanical ventilation.


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