What is a vaccine? How does it work? Are they safe?

boosters are important to protect cats, dogs, rabbits, and other animals against potentially fatal contagious diseases. Some of these diseases, like leptospirosis in dogs, can spread to humans too. But what is a vaccine? How does it work? Are they safe?

What is a vaccine?

A vaccine is a small amount of killed or inactivated virus or bacteria. When we show this to the body the immune system learns about the disease and memorises how to identify and fight this type of infection. If we come into contact with the real disease the body already knows how to destroy it.

For pet’s in the UK there are vaccinations which we consider ‘core’. These ones are most essential, usually because these diseases are the most deadly or more common. ‘Non-core’ vaccines exist for some rarer diseases or for diseases with less severe symptoms. Your vet will help you decide whether your pet requires a ‘non-core’ vaccine.

When do we start?

Newborn puppies and kittens have a small amount of protection against diseases from their mother. This protection will wear off at some point before they are 16 weeks old. To make sure every puppy and kitten receives a vaccine at a time their body will respond to it, we must give some vaccines at least twice. We usually start puppies and kittens from 8 weeks old, and rabbits from 5 weeks old.

But why do we need annual boosters?

Immunity can wear off over time. Repeating vaccinations reminds the body what the disease looks like, and keeps it prepared to attack. The immune system can’t remember some diseases as well as others, so we need to give these vaccines more often. We take great care to avoid over-vaccinating – who wants an injection that they don’t need?! Here’s where it gets technical.

If you have an up-to-date vaccination certificate from Lime Trees, you may notice the stickers aren’t the same every year. This is because dogs over one year old only need vaccinating against distemper/adenovirus/parvovirus (orange sticker) every three years. This is the same for cats, who only need panleukopaenia (green sticker) every three years. Due to short-lasting immunity dogs must be vaccinated against leptospirosis (yellow sticker) and bordetella/parainfluenza (blue sticker) vaccines annually, and cats herpesvirus/calicivirus (turquoise sticker), to make sure they are always protected. Having a booster vaccination each year is also a great opportunity to have a full service and MOT with the vet!

We keep up to date with the latest research and guidance so we know when to give which injection. For example, until very recently cats used to have leukaemia virus (grey sticker) annually, but this has now been reduced to every three years following further research showing the immunity lasts longer.

Will vaccinations harm my pet?

When choosing which vaccinations to use, we have done our research and know that they are very safe. However, any time we give an animal or a human a vaccination we ask its immune system to do something and just like with medications, it is possible to have an adverse reaction. The most common reaction is a small lump at the injection site which disappears in a few days. We might delay or avoid vaccinations if your pet has a health condition making the immune system weak, or they are on certain medications. This is usually because we want to be sure the vaccine will work properly. All our patients are individuals and our vets will discuss what vaccine schedule will give them the best protection, and then weigh up which risk is higher: the risk from contracting and suffering from the disease, or the risk from having a vaccination.

Phew, confused? Don’t worry, all our vets are trained in immunology and are on hand to answer your vaccination queries! If your pet is overdue for their vaccination, get in touch to discuss keeping them protected.