Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
PLoS One. 2010 Dec 1;5(12):e14183. doi: 10.1371/journal.pone.0014183.
In many countries, the reported pertussis has increased despite high vaccination coverage. However, accurate determination of the burden of disease is hampered by reporting artifacts. The infection frequency is more reliably estimated on the basis of the prevalence of high IgG concentrations against pertussis toxin (IgG-Ptx). We determined whether the increase in reported pertussis in the last decade is associated with an increase in the number of infections.
METHODOLOGY/PRINCIPAL FINDINGS: In a cross-sectional population-based serosurveillance study conducted in 2006-07, from a randomly selected age-stratified sample of 7,903 persons, serum IgG-Ptx concentrations were analyzed using a fluorescent bead-based multiplex immuno assay. In 2006-07, 9.3% (95%CI 8.5-10.1) of the population above 9 years of age had an IgG-Ptx concentration above 62.5 EU/ml (suggestive for pertussis infection in the past year), which was more than double compared to 1995-96 (4.0%; 95%CI 3.3-4.7). The reported incidence showed a similar increase as the seroprevalence between both periods.
Although changes in the vaccination program have reduced pertussis morbidity in childhood, they have not affected the increased infection rate in adolescent and adult pertussis. Indeed, the high circulation of B. pertussis in the latter age-categories may limit the effectiveness of pediatric vaccination.
尽管疫苗接种率很高，但在许多国家，报告的百日咳病例仍有所增加。然而，由于报告的人为因素，准确确定疾病负担受到阻碍。根据针对百日咳毒素（IgG-Ptx）的高 IgG 浓度的流行率，可以更可靠地估计感染频率。我们确定在过去十年中报告的百日咳增加是否与感染人数的增加有关。
方法/主要发现：在 2006-07 年进行的一项基于人群的横断面血清学监测研究中，我们从随机选择的年龄分层样本中抽取了 7903 人，使用荧光珠基多重免疫测定法分析血清 IgG-Ptx 浓度。在 2006-07 年，9.3%（95%CI 8.5-10.1）的 9 岁以上人群 IgG-Ptx 浓度高于 62.5 EU/ml（提示过去一年发生百日咳感染），这一比例比 1995-96 年（4.0%；95%CI 3.3-4.7）高两倍多。报告的发病率与两个时期的血清阳性率相似增加。
尽管疫苗接种计划的变化降低了儿童百日咳的发病率，但它们并未影响青少年和成人百日咳的感染率增加。事实上，在年龄较大的人群中，B. pertussis 的高循环可能会限制小儿疫苗接种的效果。
