Diphtheria – Results of an Immunological Survey

Overview

The objective of the immunological survey (IS)was in addition to assessment of the overall immunityof the Slovak population against diphtheria to test the effectiveness of vaccination and suitabilityof the used vaccination pattern and to assess the persistence of antibodies against diphtheria inmore advanced age, and possibly the need of revaccination. The sera were tested by means of theneutralization test on cell cultures. The level of diphtheria antitoxin was assessed quantitatively. Inthe reaction standards were used – diphtheria toxin 79/1 1000 Lf, produced in the National Instituteof Public Health and the Environment Bilthoven, Netherlands and the diphtheria antitoxin Diphtheriaantitoxin equine British Standard 66/153, obtained from WHO International Laboratory forBiological Standards, Great Britain. The overall immunity assessed on a nationwide scale inSlovakia was adequate (88:2%). In the child population the level of antibodies correlated well withthe administration of individual vaccinations against diphtheria. In 6-to 10-year old children theserum positivity was as high as 100%, in older children it did not drop below 95%. A more markeddecline of serum positivity was found in the population above 40 years. The highest proportion ofsensitive subjects was in the group of 50–59-year-old ones (45.2%). The antidiphtheritic immunity ofthe population under 50 years is very good. Inadequate immunity of adults above 50 years revealedthe need of administering a booster dose against diphtheria which will have a positive impact onthe antibody level of this age group of the population.

Key words:
diphtheria – immunological survey.