This article on mucosal immunity provides helpful context for intranasal vaccines:<p>> Many microbes, including the coronavirus, enter the body through the mucosa — wet, squishy tissues that line the nose, mouth, lungs and digestive tract — triggering a unique immune response from cells and molecules there. Intramuscular vaccines generally do a poor job of eliciting this mucosal response, and must instead rely on immune cells mobilized from elsewhere in the body flocking to the site of infection.<p>> Given the potency and rapid spread of the coronavirus, some say it makes sense to develop vaccines for the airway as well as the more standard jabs. “Knowing how potent mucosal responses can be against a viral pathogen, it would be ideal to be thinking about mucosal vaccines,” said Akiko Iwasaki, an immunologist at Yale University.<p><a href="https://www.nytimes.com/2020/07/14/health/coronavirus-nasal-vaccines.html" rel="nofollow">https://www.nytimes.com/2020/07/14/health/coronavirus-nasal-...</a><p>And here’s one of the first studies using a mouse model (AFAIK) for SARS-CoV-2 if you want to see how that works: <a href="https://rupress.org/jem/article/217/12/e20201241/151999/Mouse-model-of-SARS-CoV-2-reveals-inflammatory" rel="nofollow">https://rupress.org/jem/article/217/12/e20201241/151999/Mous...</a>
This is an interesting and well-done paper. It is, however, difficult to evaluate these mouse studies because, unlike human ACE2, mouse ACE2 doesn't facilitate SARS-CoV-2 cell entry. Therefore, they had to first deliver hACE2 either with an intranasal adenovirus injection, or use transgenic mice expressing hACE2 in a pattern that does not recapitulate its expression in humans.<p>It does seem like they do an especially good job at blocking infections in the respiratory system, but that's both the system that they primed for infection and where they provided the ChAd vaccine, so I don't know how fair of a comparison the intramuscular injection experiments are.
This is really interesting. Obviously evidence in mice is a long way away from demonstrated safety & efficacy in humans but I'll be curious to see where this one goes. If non-healthcare-professionals could be trained to administer a nasal vaccine (the way many non-hcps are able to carry and administer nasal naloxone in case of opiate overdose), it seems like it might potentially make vaccine adoption faster or more widespread.
I'm very interesting if we switched to using nasal vaccines, would it help soothe out the rabid anti-vaxxers?<p>A large part of the movement IMO stems from the fact that subconsciously, humans tend to associate long sharp needles = pain = bad
This is right out of Contagion! I don’t understand why even I feel like an injected vaccine vs. a nasal one seems so different. Injected vaccines seem a bit scary and unknown but I can totally get behind a nasal spray. Very weird.