F2 and pertussis: The purpose of this study was to estimate incidence of pertussis in the population before and after the COVID-19 pandemic by analyzing the anti-PT IgG and anti-FHA IgG antibodies in healthy Chinese population from 2018 to 2021, so as to understand the actual infection level of pertussis in the population of Jiangsu, China, as well as to provide suggestions for the optimization of pertussis immunization programs in China.