1ST CITY CLINICAL HOSPITAL

Post-vaccination hyperthermia in a child

26.11.2024

Why does the temperature rise after vaccination?

Vaccinations are given to create immunity (resistance) to pathogens in a child. A vaccination is a foreign agent for the body. A vaccine contains a weakened viral or bacterial infection. In some situations, a protein substance of a cell in the form of a polysaccharide is used (produced from the waste products of bacteria). All these components are commonly called by one word in practice - antigen (any substance that the body considers foreign or potentially dangerous and against which the body, as a rule, begins to produce its own antibodies). That is, when they are introduced, the immune system starts its work and begins to produce the necessary antibodies (immune response).

Many bacteria and viruses have increased susceptibility to high temperatures, and the body produces antibodies better precisely during hyperthermia. Hyperthermia is a normal response of our immune system to the introduction of various infectious agents.

The likelihood of a fever after vaccination also depends on the purity, degree of purification and properties of the vaccine. For example, side effects in the form of fever are less common with acellular pertussis vaccines than with whole-cell vaccines.

Then another question arises: why do some children have a fever and others do not? Here, everything depends on the individual characteristics of the body. Some children suffer from the same infection with different conditions.

Such temperature reactions are explained by two reasons:

• the smaller the child, the lower the likelihood of hyperthermia;
• with each subsequent vaccination (for the same disease) the probability and degree of temperature rise increases.

Why does this phenomenon occur? When immune bodies are first introduced, the body produces so-called memory cells. They are responsible for the emergence of a protective reaction during repeated infection. After the second vaccination, the immune response occurs faster, and therefore the risk of developing side effects increases.

Most side effects are mild and last no more than 1-2 days. If any adverse reaction occurs after 48 hours of vaccination with an inactivated vaccine, then most likely the vaccination has nothing to do with it. The most common cause of fever and some other reactions in young children is teething, in older children - colds. In any case, a fever reaction that persists for more than 3 days after vaccination requires a doctor's examination of the child.

In case of vaccination with live vaccines, side effects usually occur 5-12 days after vaccination. The measles vaccine sometimes causes a fever, runny nose, sore throat, coughing, conjunctivitis, and sometimes a small rash similar to measles. All these symptoms go away on their own in 2-3 days. The rubella vaccine is often accompanied by a short-term rash similar to rubella itself. This rash does not require treatment, it is not dangerous and goes away on its own in 1-2 days, without a trace. The mumps vaccine also sometimes causes fever and a slight increase in the parotid salivary glands. In case of vaccination with a live polio vaccine, there are practically no side effects, but after vaccination it is necessary to observe the rules of personal hygiene (a separate bed, potty, separate bedding, clothes from other children, and isolation of the vaccinated child in the family from those with immunodeficiency).

Hyperthermia after vaccination itself cannot serve as a sufficient reason to refuse other vaccines. Too many factors can affect vaccination, and other vaccines can be tolerated much easier. What to do next should be decided by the attending physician, who has more complete information about the state of the body.

Zhukovskaya Anastasia Aleksandrovna, anesthesiologist-resuscitator of the pediatric department of anesthesiology and resuscitation (with intensive care unit for newborns) of the highest qualification category.