Could the rise in Omicron represent persistent sinus infection?
The epidemiology of Omicron suggests there is a piece of the COVID-19 puzzle that is missing. Between 4% and 6% of people in the UK are infected with Omicron – how can this occur without achieving herd immunity in a few months? Whilst I’m not an epidemiologist, I would estimate that over 60% of the population would be infected within 2 months (based on a similar percentage being infected every 5 days), and thereafter infection levels would decline, rather than increase.
Omicron has the capability to infect not just the upper airways, but also the sinuses, which is different from prior SARS-COV2 viral variants. Could this mean that virally infected cells are less accessible to the immune system?
“Interestingly, we observed the Omicron infected NP+ nasal and sinus respiratory cells was increased 7–10-fold when compared to WA1 or Delta, suggesting an olfactory to respiratory tropism transition with the Omicron variant.”
Chen, Mengfei, et al. "Evolution of nasal and olfactory infection characteristics of SARS-CoV-2 variants." bioRxiv (2022).
One possibility is that the viral infection is not fully cleared by the immune system and remains persistent, but hidden, in the sinuses. This concept has never been shared prior to this post. It may explain the recurrent infections that are being observed, as many people are not actually cleared of the virus.
“But reinfections within 90 days can happen, as shown by a study in Denmark, a country that experienced a surge of omicron cases beginning in November 2021, caused by peaks of omicron subvariants BA.1 and BA.2 merging into each other.”
Wilson C. How quickly can you catch covid-19 again? New Sci. 2022 May 14;254(3386):9. doi: 10.1016/S0262-4079(22)00824-7. Epub 2022 May 13. PMID: 35603060; PMCID: PMC9106377.
“Why are humans equipped with paranasal sinuses? This question has occupied researchers in the area for hundreds of years but still today, there is no clear answer for the physiological significance of these enigmatic cavities.”
Lundberg, Jon O. "Nitric oxide and the paranasal sinuses." The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology: Advances in Integrative Anatomy and Evolutionary Biology 291.11 (2008): 1479-1484.
What could this mean going forward?
If the SARS-COV2 virus continues to replicate in the paranasal sinuses, the potential for inflammatory effects on the central nervous system could be increased as the sinuses are located in close contact with meningeal regions of the brain. This is especially true of the sphenoid sinus which is just below the pituitary gland.
Neurological manifestations associated with Omicron could increase dependent on the duration of infection in these sinuses.
Thirty-seven percent of children and adolescents hospitalized with COVID-19 had neurological symptoms, a study conducted by National Taiwan University Hospital (NTUH) found. (Taipei Times July 10, 2022)
Whilst just an idea generated through reflection and research, it could have huge significance for future management of the longer term outcomes of COVID-19.
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