Why does my cat (or doggo) need a rabies vaccination every year, but humans only need a couple rounds (depending on vaccine) and maybe a booster every 10



Why does my cat (or doggo) need a rabies vaccination every year, but humans only need a couple rounds (depending on vaccine) and maybe a booster every 10

In: Biology

Humans don’t get rabies vaccines unless they’ve work in an environment that puts that at risk for exposure or have already been exposed as a means of post-exposure-prophylaxis.

Pets get rabies boosters every year largely out of an abundance of caution. There have not been any good studies that show how long immunity lasts in pets. Because of the seriousness of the disease to both pets and humans, rather than have a situation where they only get vaccinated every 3 years but the immunity only lasts 2, laws require vaccination every year to ensure 100% immunity at all times.

The other poster provides a great explanation but there are additional factors:

1. The vaccine: not all vaccines are alike. There are many different kinds of vaccines like live vaccines and killed vaccines. Different vaccines stimulate the immune system in different ways. Some are better at getting the immune system to remember the disease for longer periods of time so the vaccine only needs to be given every decade or so. Other vaccines are really bad at getting the immune system to remember the disease and the immune system forgets quickly so you need to give the vaccine more often, say every year. For example, you can get both 1y and 3y rabies vaccines for dogs and cats.
1. Along the same thread some vaccines are simply better at stimulating an immune response. In any given population a certain number of people (or pets) will not respond to a vaccine. They get the vaccine but the vaccine does not work for many different possible reasons. For those vaccines that don’t tend to work as well having shorter boosting intervals may help increase population protection. Giving regular boosters helps make sure that most of the population for most of the time is protected.
2. Not all vaccines work the same. Some protect individual from getting the disease all together. Other vaccines help protect the individual from spreading the disease – they still get the disease they just don’t shed it. Other vaccines only help lessen the symptoms, you still get the disease and you still get sick but you are less likely to have fatal or serious symptoms or complications from the disease. This may impact how often the manufacture recommends giving the vaccine.
2. The disease: some diseases mutate really fast and so a vaccine given last year may not protect for a new strand of the same disease this year. Influenza or the Flu is a really great example of a disease that changes quickly from one season to the next. Researchers need to predict which strain will become the dominant one for the following flu season, develop a vaccine for that strain, and then manufacture that vaccine in time for the flu season. Sometimes they get it right sometimes they get it wrong.
1. Some diseases are more serious than others. For example, most dogs clear kennel cough (bordetella) on their own and the bordetella vaccine has poor efficacy so most veterinarians consider this vaccine to be a non-core vaccine. Only high risk patients would be recommended to receive this vaccine. Rabies on the other hand is a fatal disease once symptoms appear and presents a signitifcant risk to human health, our vaccine for rabies is also pretty good so for these reasons the rabies vaccine is a core vaccine, one that veterinarians would recommend to all their patients.
3. Titres: in both humans and animals we can take a blood sample that measures how well the immune system remembers a vaccine by measuring the number of titres a person has to a particular disease. People who work with animals will have gotten their rabies vaccine. Every few years you have your blood drawn and your rabies titres measured. If they are sufficiently high you don’t need a booster, but if they are low then you need to get revaccinated for rabies. Some people need to get rabies boosters regularly every few years, and others can go their whole lives without needed a single boost. Animals are likely the same – some individual animal’s immune systems will take to the vaccine better than others. Just like in humans we have the ability to measure titres in our pets, but most people don’t bother because the blood test is in many cases more expensive and more time consuming than getting the vaccine itself. Not to mention drawing blood from a pet can be a much bigger undertaking than giving them a simple under the skin injection.