Seroprevalence of pertussis among adults in China where whole cell vaccines have been used for 50 years.

To estimate the true incidence of pertussis in Chinese adults who are at a childbearing age.
A total of 897 serum samples from healthy individuals aged 20 to 39 years were selected randomly from a large number of serum samples collected in 2010 in Beijing, China. Anti-pertussis toxin (Ptx) IgG antibodies were determined with the Viron/Serion ELISA kits using purified Ptx as a coating antigen.
Only 124 (13.8%) were found to have undetectable anti-Ptx IgG antibodies. The mean concentration was 13.76 IU/ml (95% CI, 12.37∼15.15). Forty-six (5.1%) subjects had anti-Ptx IgG levels greater than or equal to 40 IU/ml, indicative of a pertussis infection, and nine (1%) had IgG antibodies greater than or equal to 100 IU/ml, indicative of a recent infection within a year. No significant differences were observed between age groups of 20∼29 and 30∼39 years, or between genders.
Our study showed that about 5% of adults aged 20∼39 years had positive anti-Ptx IgG antibodies, suggesting that adult pertussis is common in China. Giving a booster vaccination to pregnant women should possibly be considered in order to protect young infants who are too young to be vaccinated in this countr

Authors:Chen Z1, Zhang J2, Cao L1, Zhang N1, Zhu J1, Ping G1, Zhao J3, Shuming L4, Qiushui H5.
Journal:J Infect. 2016