Immunization is an essential tool for the prevention of infectious diseases. The introduction of universal immunisation programmes has been a great boon to children in many countries. It has made it possible to control recurrent epidemics of serious diseases, causing thousands of deaths or severe complications. This is particularly true of smallpox, polio, measles, whooping cough and hepatitis B.

However, these diseases (with the exception of smallpox) are still present in our environment and maintaining so-called population (group) immunity requires the prophylactic immunization of successive generations of children. Epidemiologists estimate that the risk of a new outbreak occurs when the percentage of children vaccinated against a given disease falls below 90% of the population. With regard to many vaccinations in Poland, the situation is dangerously close to this limit, which threatens a significant increase in the incidence of, for example, measles or whooping cough.

Such events have been observed in the past in many Western countries, such as the UK, where, due to fear of complications of pertussis vaccination, the proportion of children immunised was significantly reduced in the 1980s. This resulted in epidemics of full-blown severe cases of pertussis, which in many cases ended in deaths or severe neurological complications. Analyses carried out after this period by English epidemiologists have shown that although vaccination for pertussis carries some risk of post-vaccination complications, this risk is 20 times lower than the risk arising from a child possibly contracting pertussis who has not been vaccinated.

Specialists overseeing the implementation of immunization in children in Poland indicate that many children are not vaccinated despite the fact that they report to the District Clinics. The reason for this is the overly frequent exemption from vaccination despite the fact that the child's condition (or some chronic disease) is not a formal contraindication to vaccination. This precautionary approach of many parents and doctors is not at all beneficial for the child. "protected" from possible complications of vaccination, since contracting an infectious disease carries a risk of complications greater than post-vaccination complications. In addition, it should be remembered that it is precisely the "weaker" children, chronically ill or simply those who are frequently ill, who are at particular risk in the event of contracting, for example, whooping cough or measles, and the timely completion of all vaccinations is more important for these children than for their healthy counterparts.