HOW VACCINES WORK

Vaccines introduce a safe version of a bacteria or a virus into the body; they stimulate the immune system to make defences in case the animal encounters the real bacteria or virus. This allows the immune system to react faster and, hopefully, defeat the bacteria or virus before it makes the animal unwell.

Dog vaccines can either be made of live attenuated bacteria or virus, or dead bacteria. Distemper, hepatitis, parvovirus, bordetella, and parainfluenza are usually attenuated live vaccines, whereas leptospirosis is an inactivated (dead) vaccine. Live vaccines produce a longer-lasting immune response than dead vaccines, which is why leptospirosis vaccines must be repeated every year.