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Open Access Research article

Seroprevalence of Immunoglobulin G antibodies against pertussis toxin among asymptomatic medical students in the west of Iran: a cross sectional study

Seyyed Hamid Hashemi1, Mitra Ranjbar2*, Mehrdad Hajilooi3, Mohammad-Ali Seif-Rabiei4, Mahnaz Bolandi1 and Javad Moghimi2

Author Affiliations

1 Depatment of Infectious Diseases, Hamedan University of Medical Sciences, Hamedan, Iran

2 Depatment of Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran

3 Depatment of Immunology, Hamedan University of Medical Sciences, Hamedan, Iran

4 Depatment of Social Medicine, Hamedan University of Medical Sciences, Hamedan, Iran

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BMC Infectious Diseases 2009, 9:58  doi:10.1186/1471-2334-9-58

Published: 9 May 2009



Pertussis is a highly communicable, vaccine-preventable respiratory infection. Immune response against this disease can be induced by infection or vaccination. Protection after childhood vaccination is minimal after ten years. Our aim was to assess pertussis immunity state in a population of healthy young medical students.


In this seroepidemiological survey, blood samples were obtained from 163 first-year medical students in Hamedan University, Iran. Serum level of IgG against pertussis toxin (IgG-PT) was measured by Enzyme-Linked Immunosorbent Assay (ELISA) method. For qualitative assessment, IgG-PT levels more than 24 unit (U)/ml were considered positive. Data was analysed qualitatively and quantitatively considering gender and age groups.


There were 83 males and 80 females, with a mean age of 19.48 years, Prevalence of IgG-PT was 47.6% with mean level of 71.7 u/ml (95% confidence interval: 68.1–75.3). No statistically significant difference was observed with respect to sero-positivity of IgG-PT between males and females (45 cases (54%) vs. 34 cases (42%); P = 0.06). Mean IgG-PT levels in males and females were 84 U/ml and 58.8 U/ml, respectively (P = 0.91).


A considerable proportion of our study population with a positive history of childhood vaccination for pertussis was not serologically immune to pertussis. A booster dose of acellular pertussis vaccine may be indicated in Iranian, medical students regarding their serologic conditions and outstanding role in health care systems.