ABSTRACT
Objective This cross sectional study was designed to estimate the intensity and duration of DTP by analyzing serum anti-Bordetella pertussis toxin (PT) IgG antibodies among children in Shanghai. The results may provide scientific evidence for developing vaccination protocol and assessing vaccination effect. Methods Blood samples were obtained from 372 children (0-18 years of age) in Shanghai. The serum level of anti-PT IgG was determined by commercial ELISA kits. Anti-PT IgG level ≥30 IU/mL was defined as positive if no pertussis vaccine was vaccinated in the past year, which indicates recent contact with Bordetella pertussis. Anti-PT IgG level ≥100 IU/mL suggests an acute infection. Results The mean concentration of anti-PT IgG antibody was 16.21 IU/mL in the 372 subjects. Serum anti-PT IgG was positive (≥30 IU/mL) in 42 (11.29％) children. The highest positive rate was found in the age group of ＜3 years old (18.60％), followed by the age group of 10-12 years old (11.43％), and the lowest positive rate in the age group of 3-5 years old (7.46％). The mean level of anti-PT IgG antibody was 21.82 IU/mL in the age group of ＜3 years old, 21.16 IU/mL in the age group of 10-12 years old, and the lowest (9.74 IU/mL) in the age group of 6-9 years old. Conclusions Atypical B. pertussis infection is prevalent among younger children in Shanghai. Booster dose of pertussis vaccine may be useful in reducing the incidence of pertussis in children.