> So let me ask a dumb question for someone with actual biomedical knowledge. Are they saying that infection of the CNS is somehow easier through the nose, in w

> So let me ask a dumb question for someone with actual biomedical knowledge. Are they saying that infection of the CNS is somehow easier through the nose, in which case high-quality face masks actually do matter? The olfactory receptors (nerves that smell) are among the most exposed nerves of the body, and IIRC they are single cells stretching from the mucus membrane in your nose all the way to the brain. And because smell is such an evolutionary ancient function, the relevant brain region is really close to the centre of the brain (and brainstem). So it's really just two hops from the outside world to the command post of your autonomous nervous system (i. e. breathing)