A definition of 'vaccine' is 'a biological preparation that provides active acquired immunity to a particular infectious disease'. Otherwise it is merely a drug or medicine. 'Vaccine' is not appropriate for covid. Dealers could say they sell heroin as a vaccine to prevent despair.
If the drug cartels (AZ and the others) and the politicians discovered that a vaccine for covid that contained heroin was the cure would you take it particularly if it required boosters now and then. Then they even advertised that the side effects were minimal and not all bad.
Regardless of what works here is the question: What is the moral difference of someone peddling heroin to someone peddling a cure for covid when both are more interested in profit than medical outcomes.