That natto was a healthy food to eat we knew already, the Japanese have been eating natto for a thousand years after all. But that natto with its very high vitamin K2 content (7-12 mcg per gram) could protect us from the coronavirus in particular is news to us. A recent small study conducted at the University of Maastricht, The Netherlands, points in that direction. More studies need to be performed, but this is promising. Once again it comes to show that traditional foods might hold part of the answer to modern-day problems.
Check out these links to get more of the science behind natto and K2:
https://pubmed.ncbi.nlm.nih.gov/10874601/
https://pubmed.ncbi.nlm.nih.gov/11356998/
https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/#h3
Check out the story at this link: https://www.institutefornaturalhealing.com/2020/06/the-japanese-secret-that-may-lower-coronavirus-risk/