Harvest mites despite annual booster

[Tigerlion123]

We went to the vet for our cat's annual booster a few weeks' ago. The cat now has harvest mite bites near its ears. Should the booster have protected him against this?
What can I do to stop
Him itching/ attracting the mites? A friend said I could get a spray to spray on him. Does anyone know which one is good?

For harvest mites you need the spray, spot on doesn’t kill them according to our vet. I think we had frontline. They are evil little things.

Vaccinations do not cover for harvest mites. Can you actually see the little orange mites, they are visible to the naked eye. It is a little early in the season for them we usually see them late August, September and October as their Latin name Neotrombicula Autumnalis suggests they are more an autumn problem.