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.
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.
This is a good question. The vaccinated immune system may never develope a sufficient number of mucosal antibodies to rid the virus due to OAS.
Being jab free for over ten years now, I can say that I have not had to deal with a sinus infection for years and they were a chronic problem for me in the past.
Thank you for paying attention to NALT immunity in the URT. Please publish some posts about intramuscular vaccine induced Abs, T cells in the URT with particular focus to neutralizing capacity and half-life of vaccine induced immune cells there. Enlightening topic for the C19 pandemic.
With regard to the present post I have the following remarks:
- Nasal sinuses are not immunoprivileged tissues of mammalians. Typical immunoprivileged tissues of mammalians include the pregnant uterus, eye, brain, and testis. Therefore, virus does not hide there, while the viral particles may remain there for prolonged period of time;
- Even seroconverted individuals may get reinfected when exposed to high loads of pathogen. Without sanitation plagues would not have been stopped in Middle Ages. High viral loads of SARS-CoV-2 is hard to reduce without nasal/oral hygiene and ventilation while the virus can easily reside in multiple reservoirs: pets and livestock, for instance.
- Omicron BA.5 have managed to develop reliance on multiple cell surface proteins to ensure membrane fusion. While Delta was primary dependent on TMPRSS2, BA.5 uses C-type lectin, Adam10 or 17, etc, therefore BA.5 tissue tropisms is not limited to ACE2 dominant cell lines. This is serious concern that prolonged sub-optimal immune pressure may push the virus to immunoprivileged tissues. And with the respiratory virus only BBB protects brains from this risk.