Al-Rashedi Mohammed1, Elrashdy M. Redwan1,2
and Hussein A Almehdar1

1Department of Biological Sciences, King Abdul Aziz University, Jeddah. KSA.
2Therapeutic and Protective Proteins Laboratory, Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications, New Borg EL-Arab 21934, Alexandria, Egypt.


The aim of this study was to determine the prevalence of diphtheria by a cross-sectional in Saudi population. The size of the population consisted of five-hundred healthy subjects from the western regions of Saudi Arabia from six months to 96 years age. ELISA assay kits was used to titers anti-diphtheria IgG. According to the widely used criteria, 31.7% of the total population was susceptible to diphtheria (IgG level<0.15 IU/ml), 15.7% had basic protection (0.15–1.0 IU/ml), and 52.6% had full protection (>1.0 IU/ml). The majority (82%) of the population from 6 months to 96 years had a protective level of IgG against diphtheria. The frequencies of susceptibility were relatively high in middle-aged periods (30.2 – 37.5% of subjects aged 21–50 years). Significantly, more females (20.7%) than males (15%) were unprotected against diphtheria. In conclusion, monitoring immunization status and administering the diphtheria vaccine as required are essential to ensure adequate and long-lasting antibody levels.

Keywords: Diphtheria, Sero-prevalence, Immunity.