Spelled out in layman's terms, here's an opinion piece that argues for the need for a nasal vaccine as a powerful adjunct to reduce the spread of COVID:
The ideal vaccine cocktail may include injectable and intranasal components.
thehill.com
The key is the role of three different class of antibodies, IgA vs. IgG. The former protects mucous membranes from infection, while the latter has a higher concentration in the blood. The current vaccines stimulate the production of both, but far more IgG, and the IgA levels fall off much quicker too. So, in the lungs where IgG can easily penetrate the thin layer between the airways and blood vessels, a vaccinated individual retains good protection against severe illness. But the drop-off in IgA leaves the nasal passage much more vulnerable. This is why vaccinated individuals have much greater protection from severe illness, but can still catch and spread the virus, albeit in lesser quantities and for a shorter duration. So, a nasal vaccine that strongly stimulates IgA in the nasal mucosa would be a huge boon to reducing the R0 of COVID.
Maybe Disney could aerosolize this stuff for the first night of your resort stay...