It would be used, not as an alternative to the present mass slaughter policy, but to supplement it. Vaccinating cattle emerging from their indoor winter quarters could limit the spread of the disease. It would almost certainly be used only in the worst-hit areas, Cumbria and Devon, and for rare breeds and pedigree animals. It takes four days to work, and even then may not be completely effective.
Vaccinated animals can still carry the virus and pass it on, without showing any symptoms.
In many other countries meat and milk from vaccinated animals are routinely consumed. If people go abroad on holiday to countries where the vaccine is routinely used and eat meat, that meat has probably been vaccinated and has never been shown to cause any human health problems. Anyway, animals need booster shots every six months or so. Many are understandably confused. Now, though, it says there is a scientific case for selective vaccination.