There are lots of nasal sprays that may potentially be protective against covid, e.g. Betadine Cold Defence, but almost all of them are banned for sale in the U

There are lots of nasal sprays that may potentially be protective against covid, e.g. Betadine Cold Defence, but almost all of them are banned for sale in the US. But you can buy pure saline nasal spray for a couple dollars at Target, which itself is likely protective.