Nowadays, disease prevention is a professional and social imperative. For successful prevention of the disease, it is necessary to harmonize the attitudes of medical professionals. Vaccination has undoubtedly been one of the most successful prevention programme; however, but its value has been unjustifiably questioned in recent years. More specifically, the refusal and delay of parents to vaccinate their children has caused a reduction in immunisation coverage. This, along with global entanglement and migration, culminated in an increase in the incidence of diseases that were being eliminated. The most common cause of bacterial pneumonia is Streptococcus pneumoniae. Pneumonia occurs when a sufficient number of virulent pneumococci reach the lower respiratory system and overcome the defence mechanisms. Polysaccharide and conjugate vaccines are available for prevention. Pneumococcal disease affects more children under the age of five than any other disease that can be prevented by vaccination. Consequently, the experts advise prevention in the form of pneumococcal vaccination because vaccination has proven to be very effective in combating pneumococcal diseases. The incidence of invasive pneumococcal disease in children under five years of age in the European Union has been reduced by 55% five years after the introduction of 10-valent and 13-valent conjugate vaccines in national vaccination programs compared to the incidence before the vaccination. It is my opinion that the problem of vaccination should be viewed multidisciplinary, considering the views of the profession on the reasons why and against what it would be necessary to vaccinate. Particularly, practical benefits are those that are evidence-based. Through this thesis, I tried to analyse the justification for the introduction of pneumococcal vaccination in the mandatory calendar of vaccination of children, and discuss whether it has acceptable cost-benefit ratio.