Cat Vaccination

Studies show that certain vaccines can cause cancer. Nevertheless, cats should definitely be vaccinated – the risk of viral diseases is much greater.

The majority of the more than six million cats in Germany regularly receive a vaccination shot – with good reason: young cats, in particular, can become seriously ill and even die from parvoviruses, the causative agent of the cat disease if they do not have effective vaccination protection. But cat flu, leukemia, and rabies also threaten unvaccinated animals. The fact that many of these diseases have become rarer is primarily due to widespread vaccination.

However, protection against infections has its price, as has now been discovered: Studies in the USA show a connection between certain vaccinations and the occurrence of aggressive tumors at the typical injection sites, e.g. between the shoulder blades or on the side of the trunk. It is still unclear what exactly the trigger is, vaccinations against rabies and leukosis are suspected.

Vaccine Sarcomas Are Genetic

VAFS (vaccine-associated feline sarcomas), the tumors found in cats around the injection sites of the vaccines, may be genetic. dr Sagarika Kanjilal from the University of Minnesota, who has been studying the causes and occurrence of vaccine sarcoma since 1998, found changes in the p53 gene or its absence to be responsible for the tendency for these tumors to develop. p53 plays a major role in balancing cell growth and cell death and normally prevents abnormal numbers of cells in the body. The absence or mutation of p53 in the tumor cells could be the key to their development.

The scientist continues to advise all cat owners to have their animals vaccinated regularly. The best prevention is a close observation of the vaccination site. If the lump around the infected injection site begins to grow a month after vaccination, or if it is two centimeters or larger, the owner should see the veterinarian. At this early stage, the tumor can be successfully removed completely.

The Good News

So much for the bad news – now for the good: The actual risk of cancer is very small. Only between 1 and 10 cats for every 10,000 vaccinations develop cancer. The risk of becoming infected with the leucosis virus, which after all causes around a third of all tumors in cats, is significantly higher for unvaccinated free-roaming cats.

So there is no reason to deny cats these vaccinations if they are at risk of infection. Rather, in each individual case, together with the veterinarian, should be considered which vaccinations the cat really needs and at what intervals they should be given. The risk increases both with the frequency and with the administration of several vaccines together in a mixed syringe.

Not Only Kittens Should Be Vaccinated

As with any other medical measure, the necessary vaccination protection also depends on the respective patient: Is it a purely indoor cat, a show cat, a free-roaming cat, or even a companion on trips abroad? Age also plays a role: kittens and older cats are generally more at risk from viral diseases. In special life situations for the cat, additional vaccinations may be necessary, for example, if accommodation in an animal boarding house is pending. The veterinarian and cat owner should consider all of these factors so that the cat gets the vaccinations it needs while avoiding unnecessary risks. This also means that cats that are only vaccinated every three years are still examined by the vet once a year in order to detect diseases at an early stage. After all, both sides want to keep the cat healthy.

Operate In Time

Despite careful risk assessment and restrictions on the necessary vaccinations, it can happen that your own cat is affected by a tumor at the vaccination site. Then you should act quickly. Since these tumors are very aggressive, i.e. grow deep and often recur after surgery, early detection is crucial: Anyone who notices a significant swelling in their cat at the vaccination site that lasts longer than three months should definitely take a tissue sample to the vet can be removed. If the tumor is malignant, it should be surgically removed, including a wide margin of healthy tissue, so that any extensions growing in the depths can also be removed. Additional treatment with chemotherapy and/or radiation is still not widespread in Germany. However, a fourth possibility is currently being tested at the Medical Animal Clinic of the University of Munich: the use of genetically modified adenoviruses, which are injected after the operation. As a result, tumor-fighting substances are to be formed directly on the spot – without side effects in the body.

This Is How You Reduce The Risk

• Not every cat needs all vaccinations, and vaccination protection often lasts longer than a year. Discuss with your veterinarian what it makes sense to vaccinate in your specific case and at what intervals.
• Don’t go without vaccinations against cat flu and feline distemper: these vaccines are very safe and all cats, including indoor cats, are at risk. Free runners should definitely be additionally vaccinated against leukosis and rabies. The danger emanating from a leukemia infection is many times higher than the risk of vaccination.
• Rabies is also very dangerous for humans, and free-roaming cats in at-risk areas should therefore have effective vaccination protection.
• When traveling abroad, a valid rabies vaccination is mandatory, i.e. the certificate must not be older than one year and not younger than 30 days. This also applies to re-entry.
• A longer vaccination interval is only an option if the cat is not traveling: most rabies vaccines protect for up to three years.