Methods The study included 90 children aged 2 to 5 years. Three equal groups each consisting of 30 patients represented the children with allergic disorders, frequency sick children and virtually healthy children. The patients were vaccinated against S. pneumoniae. In all the children the microflora of the nasopharynx was determined before and post vaccination. All the children performed diagnostic endoscopy of the nasopharynx during prior to vaccination to specify the extent of hyperplasia of the adenoid tissue.

Results Compared to the year preceding vaccination the frequency of middle ear otitis among the frequently sick children lowered from 16,7% down to 6,7%. The duration of acute respiratory infections did not exceed 7 days even among frequency sick children. Twelve months post vaccination no S. pneumoniae were found in the pharyngeal cultures of all the children The follow-up of the pathologycally allergic children over a year post vaccination showed a decrease in degree 2–3 adenoid hyperplasia to normal from 42% down to 25%.

Conclusions Vaccination against pneumococcal infection reduces the frequency and duration of acute respiratory diseases in children and normalises the condition of the adenoid tissue, especially in children with allergic disease and frequently sick children. Thus, the number of surgical interventions on the nasopharynx of children decreases. Vaccination against pneumococcal infection should be recommended for all children, Irrespective of the presence or absence of allergic diseases