Taffix is a nasal powder spray that builds up a protective mechanical barrier against viruses and allergens in the nasal cavity. The EMA allowed them to write on their packaging insert to advertise it's clinical effects by saying:

Taffix was found highly effective in blocking several respiratory viruses including SARS-CoV-2 in laboratory studies.

The idea was conceived in March and they did a study during the Jewish New Year event which was as expect a superspreader event (orthodox Jewish people gathering in close proximity while a lot of them were infected). Among the 83 people who received the intervention only the two people who reported not consistently using the spray (you have to apply it every 5 hours) got infected while in the control group 16 out of 160 got infected. Nobody reported any side-effects.

It seems that the information took month to tickle through to us at LessWrong with ejacob writing in his shortform. Living in Europe I could simply order my Taffix on Amazon and had it delievered soon after. In the spirit of more dakka, it would make sense to everyone to get their Taffix. Maybe we could have even prevented the winter lockdown if everybody would have gotten their Taffix.