Adverse reactions of vaccines in children

Vaccines, like any other medicine, can cause adverse reactions. These reactions will almost always be mild, rarely moderate and, exceptionally, serious. Technological development and the quality of clinical trials allow the development of effective and safe vaccines . However, and again, as with any

Vaccines, like any other medicine, can cause adverse reactions. These reactions will almost always be mild, rarely moderate and, exceptionally, serious.

Technological development and the quality of clinical trials allow the development of effective and safe vaccines. However, and again, as with any other drug, only monitoring after commercialization will allow to know the real rate of adverse reactions (this monitoring is known as pharmacovigilance). Before vaccines reach pharmacies, they have undergone numerous and strict clinical trials and have proven their safety and efficacy in hundreds of thousands of children.

Reactions in children after vaccination

Adverse reactions after vaccination can be classified as follows:

1. Reactions induced by vaccination:

1a) Local reactions.

- Common: occur in 5-15% of children after vaccination. They are characterized by pain, swelling and redness at the puncture site. They are the most frequent, occurring during the first 48 hours after vaccination, and may vary in intensity individually. Cede spontaneously in 1-2 days. It can occur in up to 50% of children after administration of the DTP vaccine (diphtheria, tetanus and whooping cough).

- Rare: 1-10 cases per million doses administered. Those described are: abscess at the puncture site, local inflammatory reaction that lasts more than 3 days or local hypersensitivity reactions. None of these rare local reactions leave permanent sequelae, except for possible keloid (bulging) scars.

1b) Systemic reactions.

- Common: appear in less than 10% of vaccinated children: fever, transient irritability, muscle pain, malaise, headache, vomiting or diarrhea. All of them resolve spontaneously and without sequelae. The appearance of skin spots or urticaria is more frequent after the triple viral (measles, rubella and mumps) or chicken pox, equally mild and spontaneous resolution. Rarely, arthralgias can appear, especially due to the rubella component of the triple virus, which are resolved several weeks after vaccination.

- Rare. Less than one case per million doses administered. These include anaphylaxis, a type of severe allergic reaction that can compromise the child's life, and which can appear after taking any medication or food. It is not possible to foresee this type of immediate reaction after vaccination, but it does have treatment and is effective. Therefore, vaccines are administered in health centers, and it is recommended that children remain in the center for a few minutes after being vaccinated. Other exceptional complications would be episodes of hypotonia-hyporesponsiveness and inconsolable persistent crying, in both cases also of spontaneous resolution and without sequelae. There are some exceptional but serious neurological adverse reactions, which have been temporally related to the administration of the vaccines, although a causal link has not been established. These include: acute flaccid paralysis (related to the poliomyelitis vaccine), Guillain Barré syndrome, facial paralysis, aseptic meningitis, brachial neuritis, encephalopathies and seizures.

2. Reactions due to program errors:

Are reactions due to any error in the conservation, storage, transport, handling or administration of vaccines. For example: non-sterile injections, reconstitution errors, injections in the wrong places, inadequate transport or storage or ignoring contraindications.

3. Matching reactions:

Occur when the cause of the adverse reaction coincides with the act of vaccination. That is, it could have happened even if the patient had not been vaccinated. The best evidence to conclude that an adverse event is coincident, is that it has been diagnosed in people who have not been vaccinated.

4. Idiosyncratic reactions or of unknown cause:

They are reactions that appear in a patient after vaccination, whose cause does not correspond to any of those mentioned above and, therefore, the cause that produces them is unknown.

Why vaccinate children

Vaccines present, all, a favorable benefit / risk ratio. A possible reading by parents is that if, for example, in Spain there has been a case of diphtheria in the last 30 years, anaphylaxis seems an unacceptable risk, since a case in a million seems greater than a case in 30 years. This approach, which is very logical, would be valid if 100% of the population was vaccinated and the borders were closed.

The objective is universal vaccination, but borders make less sense every day, and obviously can not be closed. We live in a globalized world, and at any time, anywhere, whoever sits next to us on the bus, in the restaurant or at the cinema, may not be vaccinated, either by his own decision or because he has not had the luck to be able to receive vaccines, and be a transmitter of immuno-preventable diseases.

The decision to vaccinate is free. The risk that we want to assume is also. Do not vaccinate our children for fear of possible side effects is a valid approach, but we must know the risks of not vaccinating and take them, not take our hands to the head when certain diseases occur. The so-called 'anti-vaccines' philosophy is an exclusive problem of the first world. In developing countries nobody can understand that some parents do not want to vaccinate their children.