A seaweed extract called iota-carrageenan, when administered by nasal spray, has shown promise for a quick and easy way to fight COVID by trapping much of the virus before it can take hold in our bodies. 
What does research show about this approach, and does it have the potential for other anti-COVID measures?
Carrageenan Might Prevent Virus From Taking Hold in Nose
Extracted from edible seaweed, carrageenan comes in three forms: Iota, Kappa, and Lamda. It’s used in cooking to thicken foods and has been added to processed foods since the 1950s.
Later, research found this plant extract also has potent effects against the common cold virus in laboratory testing….