They tested people to check for evidence of asymptomatic infection and found that people who had two doses of the nasal vaccine showed no signs of infection after three months.
CONCLUSION. A 2-dose intranasal vaccination regimen using NB2155 was safe, was well tolerated, and could dramatically induce broad-spectrum spike-specific sIgA in the nasal passage. Preliminary data suggested that the intranasal vaccination may establish an effective mucosal immune barrier against infection and warranted further clinical studies.
https://insight.jci.org/articles/view/180784
"At least 86.2% participants who completed 2 [nasal vaccine] doses maintained uninfected status, likely without even asymptomatic infection, for at least 3 months.
https://xcancel.com/EricTopol/status/1838937705977110991#m
Seems like we are getting closer to better vaccines being approved.
Good points. Without reading deeply, my main question is how long this protection lasts? The mRNA vaccines only confer ~4 months of protection, but this seems to be an inactivated virus with full spike protein.
If this could 1) prevent infections, and 2) confer protection for up to a year, this would be a serious improvement. I know there are groups working on this in the West too, but I think they are focused on mRNA mostly and fat chance Western countries would make this widely and cheaply available to the world. It would be interesting to see a comparison in protection profiles from mRNA coding for the spike protein vs inactivated virus with spike if both end up effective when administered intranasally.