Follow the vaccination schedule in cats saves many lives each year, both in the feline species and in many others, and keeps serious diseases under control, especially in cats that go outside or are in colonies or collectivities. That is why they are of vital importance.
However, as with most drugs, they can present a series of adverse effects or unexpected reactions that should be known, however forget that the beneficial effects are much greater than the possible harm in most cases. To minimize possible adverse effects, we will always comply with the vaccination schedule according to the age and environment of our cat, according to the indications of our veterinarian and, of course, always complying with the appropriate security measures, so they can only be administered by a qualified professional, after examining the animal in order to detect any possible sign of disease that could discourage vaccination.
In this article on our site we will detail the side effects of vaccines for cats, so that you have the most information at your fingertips. range at the time of vaccinating your feline companion. We have classified vaccine reactions according to their severity into 2 large groups:
1. Mild Reactions
They are the most frequent and are characterized by a favorable prognosis. That is, they are those that usually disappear by themselves and do not usually require any type of treatmentThey usually appear within a few hours or days after vaccination and usually last from a few days to several weeks. They are related to the activation of the immune response and inflammatory processes.
The main mild reactions are described below:
Inflammation at the point of inoculation
It is usually a small painful nodule in the area where the vaccine was administered and usually disappears on its own between 2 and 5 o'clock weeks post-vaccination. They are usually associated with adjuvants, proteins or stabilizers contained in vaccines. We can soothe the area and help the inflammation disappear more quickly by applying moist heat to it and massaging it.
It is of no greater clinical importance than the slight discomfort it causes in the animal, except in cases where it is complicated by necrosis, fibrosis and/or the appearance of a abscessIn these cases we must go to the veterinarian to treat these complications. In addition, if we observe that the nodule does not diminish after the expected time, or even that it increases in size or changes its appearance, it is advisable to perform a puncture to rule out granulomas (due to chronic inflammation), abscesses (secondary infection) or even the appearance of a malignant tumor called fibrosarcoma, which we will talk about in more detail at the end of the article.
Fever
Fever in cats appears, as we have previously commented, due to the activation of the immune response and, unless it compromises the cat's quality of life, it is not necessary to treat it. On the day of the vaccine and a couple of days later, it is advisable not to exercise the patient too much or overwhelm him, providing him with a comfortable and quiet place where he can rest and recover without any problem.
Lethargy and anorexia
It is usually a consequence of the fever and usually goes away when the fever goes away. Once again, we will let the cat rest and we will not force him to eat if he does not feel like it. We can offer him moist and warm food to make it more palatable and consult our veterinarian if he is very listless or does not want to eat anything for more than 24 hours.
Vomiting and/or diarrhea
This is another of the systemic signs related to the response of the animal's immune system and the associated inflammatory process. In general it is about mild processes, but as we will see later, it can occur acutely prior to a more serious reaction, so if you observe these digestive symptoms, it is best that the veterinarian examine the animal to assess its condition and treat it if necessary.
Regional lymphadenopathy
It is part of the normal immune system response and over a few days, the size of the lymph nodes should return to normal. its usual size.
Sneezing
They can occur in the case of vaccines that are inoculated intranasally (vaccine against P. I. F) and usually last a few minutes or at most several hours after administration. They may be accompanied by sniffing and rubbing of the nose against surfaces.
two. Serious Reactions
In this case they are very rare and usually have a prognosis from moderate to severe. They can appear from the minutes after vaccination to the following weeks. The main serious reactions are the following:
Hypersensitivity reaction
These are exaggerated reactions of the immune system against substances that it would normally consider harmless. The most common hypersensitivity reaction after vaccination is type I or allergic, whose effects are immediate (between 30 minutes and 2-3 hours after administration of the vaccine). The immune system can trigger this reaction against any component of the vaccine
The symptoms associated with this type of hypersensitivity are caused by an increased release of histamine, which is an inflammatory mediator, which increases vascular permeability and causes smooth muscle contraction. When this type of reaction occurs, we can observe generalized itching, with the appearance of hives or reddening of the skin (erythema and hives) to swelling of the face and neck due to the appearance of facial and periorbital edema known as angiedema, and/or respiratory signs due to inflammation of the airways (which can become obstructed), reaching in the worst case a shock anaphylactic, which can lead to respiratory failure and sudden vascular collapse.
In cats, it can also be seen prior to anaphylaxis, acute vomiting and diarrhoea, sometimes hemorrhagic, followed by extreme lethargy, hypovolemia and respiratory and vascular failure, which can be fatal. If we observe any of these symptoms, we should urgently go to our veterinarian so that treatment can begin as soon as possible.
Fibrosarcoma at the point of inoculation
This tumor has been linked to some components of vaccines and other injectable drugs, and often appears over months or even years vaccination, being more likely the older the animal. Despite being very rare and not tending to form metastases, it is a malignant tumor very aggressive locally, which requires removal with wide surgical margins and has a high tendency to recur, so in the long term it usually has a poor prognosis.
Since it usually appears at the inoculation point, it is recommended to rotate said point and prioritize areas such as the extremities or the tail, that allows amputation if necessary and reduces the risk of recurrence. There are cases in which surgical treatment is combined with chemotherapy, depending on its evolution and depending on how advanced or extended it is.
