I think that "vaccine" is really not the right word to use for this; they sound as different as bandages and blood transfusions. But if it works as advertised, it could be useful if used in the right situation.

I do wonder if the kind of people who got vaccinated 10 times against Covid-19 will end up trying to get a sniff of this every month? Kind of like how we overuse antibiotics in cleaners. It seems like it would be best if saved for an "oh shoot" kind of situation.

Inoculation?