BC Children's Hospital Research Institute, Vancouver, Canada; Department of Pediatrics, University of British Columbia, Vancouver, Canada; Department of Pediatrics, Children's Hospital Datteln, University of Witten/Herdecke, Germany.
BC Children's Hospital Research Institute, Vancouver, Canada.
Vaccine. 2024 Sep 17;42(22):126004. doi: 10.1016/j.vaccine.2024.05.052. Epub 2024 May 25.
We recently reported a near disappearance of B. pertussis and a decline in anti-B. pertussis antibodies during the peak implementation of Coronavirus disease 2019 (COVID-19) non-pharmaceutical interventions (NPI) in 2021 in British Columbia (BC), Canada. During 2021-2023, incidence of reported B. pertussis cases remained low in BC at < 1/100,000 population. This study determined how serological evidence of B. pertussis changed after the gradual relaxation of NPI between 2021-2023.
Randomly selected blood samples from school staff 25-51 years old (n = 65) were collected yearly between 2021-2023 in the Vancouver metropolitan area, BC, Canada, and tested for anti-pertussis toxin (PT) IgG levels. Serological evidence of B. pertussis infection (thereafter "seroconversion") was defined as a quantifiable anti-PT IgG levels in subjects with anti-PT IgG levels below lower limit of quantification in the preceding year or a > 4-fold increase in anti-PT IgG levels between two subsequent years. Samples were also tested for anti-diphtheria toxoid (DT) IgG, and similar seroconversion criteria were applied to exclude seroconversion due to vaccination with tetanus-diphtheria-acellular-pertussis (Tdap).
Three subjects met seroconversion criteria for anti-PT IgG between 2021 and 2022 and 9 between 2022 and 2023, yielding a seroconversion rate of 4.6 /100 person-years and 14.9/100 person-years, P = 0.127, respectively. None of the subjects met the criteria for vaccination with Tdap. The geometric mean concentration of anti-PT IgG showed a statistically significant decrease in 2022 compared with 2021, 4.8 IU/mL IU/ml (95 % confidence interval [CI], 3.8-5.9) vs. 6.4 IU/ml (95 % CI, 4.9-8.2; p = 0.001), followed by a statistically significant increase in 2023 compared with 2022 6.5 IU/ml (95 % CI, 4.9-8.5) vs. 4.8 IU/ml (95 % CI, 3.8-5.9; p = 0.0006), respectively.
Serological evidence of B. pertussis increased between 2022 and 2023 despite low reported cases, which suggests that B. pertussis circulation resumed after relaxing of COVID-19 NPI.
我们最近报道了在 2021 年加拿大不列颠哥伦比亚省（BC）大流行期间非药物干预（NPI）高峰实施期间，百日咳博德特氏菌（B. pertussis）几乎消失，以及抗 B. pertussis 抗体水平下降。2021-2023 年期间，BC 报告的百日咳病例发病率仍保持在每 10 万人<1 例的低水平。本研究旨在确定 2021-2023 年 NPI 逐渐放松后，B. pertussis 的血清学证据如何变化。
在加拿大不列颠哥伦比亚省温哥华大都市区，2021-2023 年每年随机抽取 25-51 岁的学校工作人员 65 名，采集血液样本，检测抗百日咳毒素（PT）IgG 水平。B. pertussis 感染的血清学证据（此后称为“血清转化”）定义为在前一年抗 PT IgG 水平低于定量下限的受试者中可检测到定量抗-PT IgG 水平，或两次连续年度之间抗-PT IgG 水平增加>4 倍。还对抗白喉类毒素（DT）IgG 进行了检测，并应用类似的血清转化标准排除因接种破伤风类毒素-白喉-无细胞百日咳（Tdap）而导致的血清转化。
2021 年至 2022 年期间，有 3 名受试者符合抗-PT IgG 血清转化标准，2022 年至 2023 年期间有 9 名受试者符合抗-PT IgG 血清转化标准，血清转化率分别为 4.6/100 人年和 14.9/100 人年，P=0.127。没有受试者符合 Tdap 接种的标准。2022 年与 2021 年相比，抗-PT IgG 的几何平均浓度呈统计学显著下降，分别为 4.8IU/ml（95%置信区间[CI]，3.8-5.9）和 6.4IU/ml（95%CI，4.9-8.2；p=0.001），随后 2023 年与 2022 年相比呈统计学显著上升，分别为 6.5IU/ml（95%CI，4.9-8.5）和 4.8IU/ml（95%CI，3.8-5.9；p=0.0006）。
尽管报告的病例数量较低，但 2022 年至 2023 年间 B. pertussis 的血清学证据增加，这表明 COVID-19 NPI 放松后，B. pertussis 的传播恢复。
