You seem to be confusing treatments with vaccines by lumping them under the same broad definition. A vaccine must be taken prior to contracting the disease, and will not work if taken after. This is exactly how COVID vaccines behave, therefore they are vaccines.

Now whether a vaccine is effective or not is a separate, almost orthogonal, dimension for consideration. No single vaccine is 100% effective, so we will always have certain % of cases where vaccines did not prevent the spread of infection and resulting adverse outcomes.