Objective: To analyze the epidemiological distribution characteristics, influencing factors, and infection rates of pertussis in the population of Henan Province. Methods: From 2022 to 2023, a cross-sectional survey was conducted to investigate the permanent population in Henan Province. Enzyme-linked immunosorbent assay (ELISA) was used to detect anti-pertussis toxin IgG (PT-IgG), analyze the antibody positivity rate (≥20 IU/ml) and median concentration (MC), and estimate the pertussis infection rate based on PT IgG ≥40 IU/ml. The rank sum test was used to compare antibody levels among groups, and the χ2 test was used to compare antibody positive rates and infection rates among groups. Results: A total of 4 810 research subjects were included in this study. The overall positive rate of PT-IgG was 12.10% and MC was 3.04 (0.35, 10.36) IU/ml. There were significant differences both in positive rates and antibody levels of PT-IgG among different regions or age groups (region positive rate: χ2=134.06, P<0.001, MC: H=337.74, P<0.001; age group positive rate: χ2=45.27, P<0.001, MC: H=134.49, P<0.001). Both the positive rate of PT-IgG (25.26%) and MC (8.01 IU/ml) were the highest within one year after completing a full course of vaccination. There were significant differences in positive rates and antibody levels among people receiving different types of pertussis vaccines (positive rate: χ2=12.38, P=0.006, MC: H=17.93, P<0.001). The antibody positivity rate (35.71%) and MC (8.88 IU/ml) of the people who received cell-free pertussis inactivated poliomyelitis influenza type b (combined) vaccine throughout the course were higher than those who received other types of vaccines. The natural infection rate of pertussis was evaluated for individuals aged≥3 years who had no history of pertussis vaccine immunization within the year prior to sampling. With a high vaccination rate, the estimated infection rate of pertussis in the population was 5 757.22/100 000. The infection rates in the 3-year-old (1 940.16/100 000) and 4-year-old (1 765.68/100 000) populations were at a low level among the entire population, reaching their peak at the age of 6 (12 656.71/100 000). Subsequently, although the infection rate continued to decline, it remained at a high level and peaked again at the age of 40-49 years (8 740.39/100 000). There was a statistically significant difference in the estimated infection rate of pertussis among different age groups (χ2=53.21, P<0.001). Conclusion: The PT-IgG level of pertussis in the population of Henan Province is generally at a low level. The estimated infection rate of pertussis is much higher than the reported incidence rate. A booster dose of pertussis vaccine is recommended at 6 years old.
目的： 分析河南省人群百日咳血清流行病学分布特征、影响因素和百日咳感染率。 方法： 于2022—2023年采用横断面调查方法，调查河南省常住人口，采用酶联免疫吸附试验检测血清百日咳毒素IgG（PT-IgG），分析抗体阳性率（≥20 IU/ml）和中位数浓度（MC），以PT-IgG≥40 IU/ml估算百日咳感染率。抗体水平的组间比较采用秩和检验，抗体阳性率、感染率的组间比较采用χ2检验。 结果： 共纳入研究对象4 810名。PT-IgG总阳性率为12.10%，MC为3.04（0.35，10.36）IU/ml。不同地区、年龄组人群PT-IgG阳性率和抗体水平的差异均有统计学意义（地区阳性率：χ2=134.06，P<0.001，MC：H=337.74，P<0.001；年龄组阳性率：χ2=45.27，P<0.001，MC：H=134.49，P<0.001）。完成全程免疫后1年内PT-IgG阳性率（25.26%）和MC（8.01 IU/ml）最高；接种不同类型百日咳疫苗人群PT-IgG阳性率和抗体水平的差异均有统计学意义（阳性率：χ2=12.38，P=0.006，MC：H=17.93，P<0.001），其中全程接种无细胞百白破-灭活脊髓灰质炎-b型流感嗜血杆菌（结合）联合疫苗人群的抗体阳性率（35.71%）和MC（8.88 IU/ml）高于接种其他类型疫苗人群。对≥3岁且采样前1年内无百日咳疫苗免疫史人群进行百日咳自然感染率评估，在疫苗接种率维持在高水平的情况下，人群百日咳估算感染率为5 757.22/10万。3岁（1 940.16/10万）和4岁（1 765.68/10万）人群感染率处于全人群的低位，6岁时达到峰值（12 656.71/10万）。随后感染率虽然持续下降，但仍维持在较高水平，至40~49岁再次出现峰值（8 740.39/10万）。不同年龄组人群百日咳估算感染率的差异有统计学意义（χ2=53.21，P<0.001）。 结论： 河南省人群百日咳PT-IgG整体处于低位水平；百日咳估算感染率远高于报告发病率；建议在6岁时开展百日咳疫苗加强免疫。.