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

Hanqing He; Yao Zhu; Mingjuan Jin; Yang Zhou; Xuewen Tang; Rui Yan; Xuan Deng; Kun Chen

doi:10.1016/j.vaccine.2022.10.020

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

Vaccine. 2022 Nov 15;40(48):6956-6962. doi: 10.1016/j.vaccine.2022.10.020. Epub 2022 Oct 20.

Authors

Hanqing He¹, Yao Zhu², Mingjuan Jin³, Yang Zhou², Xuewen Tang², Rui Yan², Xuan Deng², Kun Chen⁴

Affiliations

¹ Department of Epidemiology and Biostatistics at School of Public Health, Zhejiang University School of Medicine, Hangzhou, China; Department of Immunization Program, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China.
² Department of Immunization Program, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China.
³ Department of Epidemiology and Biostatistics at School of Public Health, Zhejiang University School of Medicine, Hangzhou, China.
⁴ Department of Epidemiology and Biostatistics at School of Public Health, Zhejiang University School of Medicine, Hangzhou, China. Electronic address: ck@zju.edu.cn.

Abstract

Background: 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.

Methods: 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 < 5 IU/mL was considered undetectable, ≥20 IU/mL as seropositive and ≥80 IU/mL as an indicator of recent infection. Mathematical models were fitted for anti-PT concentrations over time in children after four doses of the pertussis vaccination.

Results: A total of 4459 participants aged 0-59 years were included in the analyses. The overall positivity rate of anti-PT was 29.80% with the highest (81.44%) rate in the 1-2 years old and the lowest (4.72%) in 10-14 years old. The GMCs of anti-PT, anti-FHA and anti-PRN for the whole participants were 9.67 (95%CI: 9.25-10.10),18.93 (18.24-19.67), and 8.99 (8.61-9.38) IU/mL, respectively. Over 50% of subjects aged ≥ 7 years had undetectable anti-PT IgG antibodies (<5IU/mL). The proportions of the populations with anti-PT IgG ≥ 80 IU/mL were approximately 0.9%, 0.3% and 1.1% among the 10-14, 15-29, and 40-59 years old groups, respectively. The power regression equation of the attenuation model after last dose of pertussis vaccine was y = 41.088x^-1.238 (R² = 0.935, p < 0.001). The fitted anti-PT concentrations was only 5.60 IU/mL at 5 years following the last vaccination dose.

Conclusion: The prevalence of pertussis decreased during the study period in the COVID-19 pandemic; however, there was still a certain proportion of adolescents and adults with evidence of recent infection. The decline in antibody levels after pertussis vaccination was observed, and booster doses are in urgent need in China.

Keywords: Antibody; Pertussis; Seroprevalence; Vaccine.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Antibodies, Bacterial
COVID-19* / epidemiology
Child
Child, Preschool
China / epidemiology
Cross-Sectional Studies
Humans
Immunoglobulin G
Infant
Middle Aged
Pandemics
Pertussis Toxin
Pertussis Vaccine
Seroepidemiologic Studies
Whooping Cough* / epidemiology
Whooping Cough* / prevention & control
Young Adult

Substances

Antibodies, Bacterial
Immunoglobulin G
Pertussis Toxin
Pertussis Vaccine