I'm seeing different approaches to try protect/alleviate against airborne viruses (e.g. HRV). Let's take some examples:
- Enzymatica ColdZyme - oral spray
- P&G Vicks First Defense - nasal spray
- Taffix - nasal spray
They all claim they stop cold viruses (and more generically airborne viruses) from spreading if used within first hours/day from the symptoms.
Note: there are some claims they can also help against SARS-CoV-2, but this is not the goal of this discussion
As far as I understand, they are acting at different layers:
- Vicks and Taffix are trying to shield the nasal cavity as it's considered the first body entrypoint
- ColdZyme shields the oral cavity as they claim that once the virus enters through the nasal cavity, it will be moved from the nasal cavity to the throat by the action of the cilia
I also hear that there is some research going on about SARS-CoV-2 vaccines through nasal spray, which makes me think that nasal cavity protection is the common used approach.
If so, why Enzymatica decided to go through the route of oral cavity protection? Wouldn't be a much less effective scenario as the virus already started its replication in the nasal cavity and it might be already late?
Though on the other hand, by protecting only the nasal cavity, wouldn't be the mouth the other main entrypoint for airborne viruses, which would be left unprotected?
I'm trying to understand the reasons behind choosing one approach instead of another for protecting again the same viruses family.
Perhaps the nasal cavity is by far the biggest risk and only a small percentage of infections (SARS-CoV-2 included) happen by "mouth"/oral cavity?