RESUMO
Pertussis or whooping cough is a highly communicable, vaccine-preventable acute respiratory tract disease, caused mainly by Bordetella pertussis. In this study, serosurveillance of IgG antibodies against pertussis toxin was carried out in healthy children, aged 3 months to 12 years, from the multiethnic cities of Islamabad and Rawalpindi, Pakistan. Kruskal- Wallis test was applied to determine the difference among groups. The results showed that the average values of pertussis toxin IgG dropped down significantly with age after getting the first dose in first 2 years [p < 0.001]. Therefore, the researchers suggest introduction of booster vaccination with DTaP at second year of life and school going age to reduce the risk of getting B. pertussis infection