The decline in immunity and circulation of pertussis among Chinese population during the COVID-19 pandemic: A cross-sectional sero-epidemiological study

•We conducted the serological investigation of Bordetella pertussis in among populations of different ages in China during the COVID-19 pandemic.•To the best of our knowledge, this is the first study to evaluate the immunity of pertussis with anti-PT, anti-FHA, and anti-PRN antibodies in China.•The prevalence of pertussis had decreased during the COVID-19 pandemic, but there was still a certain proportion of adolescents and adults exhibiting evidence of recent pertussis infection.•The waning of antibody levels after pertussis vaccination were occurred, and an extra booster dose is highly recommended at the age of 6 years by replacing DT with DTP. In recent years, the resurgence of pertussis has posed a public health challenge in many countries. This study aimed to evaluate the immunity levels against pertussis among populations of different ages in China. We conducted a cross-sectional serological survey in Zhejiang Province, China in 2020. Serum IgG antibodies against pertussis toxin (anti-PT), filamentous hemagglutinin (anti-FHA), and pertactin (anti-PRN) were quantitatively measured. The geometric mean concentration (GMC) of three antibodies was calculated. An anti-PT level