Diphtheria immunity status in Egypt

Area of Science:

• Immunology
• Epidemiology
• Public Health

Background:

• Corynebacterium diphtheriae causes diphtheria, a potentially fatal respiratory illness.
• Maintaining herd immunity requires high population immunity levels.
• Assessing diphtheria immunity in diverse populations is crucial for public health strategies.

Purpose of the Study:

• To evaluate the immune status against diphtheria in a representative Egyptian population.
• To identify population subgroups with inadequate protection against diphtheria.
• To inform public health interventions for diphtheria prevention.

Main Methods:

• A cross-sectional study involving 709 healthy individuals across Egypt.
• Serum IgG antibody levels against diphtheria toxoid were measured using Enzyme-linked immunosorbent assay (ELISA).
• Immunity was categorized based on antibody concentration (IU/ml): susceptible (<0.01), basic protection (0.01-0.09), and full protection (≥0.1).

Main Results:

• 23.9% of the population exhibited susceptibility to diphtheria (IgG <0.01 IU/ml).
• 43% had basic protection (0.01-0.09 IU/ml), and 33.1% were fully protected (≥0.1 IU/ml).
• Decreased antitoxin antibody levels were observed in individuals over 60 years old, with females showing higher susceptibility than males.

Conclusions:

• A notable proportion of the Egyptian population remains susceptible to diphtheria.
• Age and sex are significant factors influencing diphtheria immunity levels.
• Booster immunizations are recommended for susceptible age groups to enhance population immunity.