Department of Paediatrics & Child Health, Groote Schuur Hospital, University of Cape Town, Main Road, Observatory, 7925, Cape Town, Republic of South Africa.
Vaccines for Africa Initiative, School of Public Health and Family Medicine, University of Cape Town, Anzio Road, Observatory, 7925, Cape Town, Republic of South Africa.
BMC Med. 2020 Aug 28;18(1):233. doi: 10.1186/s12916-020-01699-3.
An effective vaccine against Bordetella pertussis was introduced into the Expanded Programme on Immunisation (EPI) by WHO in 1974, leading to a substantial global reduction in pertussis morbidity and mortality. In low- and middle-income countries (LMICs), however, the epidemiology of pertussis remains largely unknown. This impacts negatively on pertussis control strategies in these countries. This study aimed to systematically and comprehensively review published literature on the burden of laboratory-confirmed pertussis in LMICs over the 45 years of EPI.
Electronic databases were searched for relevant literature (1974 to December 2018) using common and MeSH terms for pertussis. Studies using PCR, culture or paired serology to confirm Bordetella pertussis and parapertussis in symptomatic individuals were included if they had clearly defined numerators and denominators to determine prevalence and mortality rates.
Eighty-two studies (49,167 participants) made the inclusion criteria. All six WHO regions were represented with most of the studies published after 2010 and involving mainly upper middle-income countries (n = 63; 77%). PCR was the main diagnostic test after the year 2000. The overall median point prevalence of PCR-confirmed Bordetella pertussis was 11% (interquartile range (IQR), 5-27%), while culture-confirmed was 3% (IQR 1-9%) and paired serology a median of 17% (IQR 3-23%) over the period. On average, culture underestimated prevalence by 85% (RR = 0.15, 95% CI, 0.10-0.22) compared to PCR in the same studies. Risk of pertussis increased with HIV exposure [RR, 1.4 (95% CI, 1.0-2.0)] and infection [RR, 2.4 (95% CI, 1.1-5.1)]. HIV infection and exposure were also related to higher pertussis incidences, higher rates of hospitalisation and pertussis-related deaths. Pertussis mortality and case fatality rates were 0.8% (95% CI, 0.4-1.4%) and 6.5% (95% CI, 4.0-9.5%), respectively. Most deaths occurred in infants less than 6 months of age.
Despite the widespread use of pertussis vaccines, the prevalence of pertussis remains high in LMIC over the last three decades. There is a need to increase access to PCR-based diagnostic confirmation in order to improve surveillance. Disease control measures in LMICs must take into account the persistent significant infant mortality and increased disease burden associated with HIV infection and exposure.
1974 年，世界卫生组织（WHO）向扩大免疫规划（EPI）中引入了一种针对百日咳博德特氏菌的有效疫苗，这导致全球百日咳发病率和死亡率大幅降低。然而，在低收入和中等收入国家（LMICs），百日咳的流行病学仍然知之甚少。这对这些国家的百日咳控制策略产生了负面影响。本研究旨在系统和全面地回顾过去 45 年 EPI 期间在 LMICs 中实验室确诊的百日咳负担的已发表文献。
使用常见和 MeSH 术语搜索电子数据库中的相关文献（1974 年至 2018 年 12 月），以确定百日咳。如果使用 PCR、培养或配对血清学方法来确认有症状者中的百日咳博德特氏菌和副百日咳博德特氏菌，并明确规定了确定流行率和死亡率的分子和分母，则将符合纳入标准的研究纳入。
82 项研究（49,167 名参与者）符合纳入标准。所有六个世界卫生组织区域都有代表，大多数研究是在 2010 年后发表的，主要涉及中上收入国家（n=63；77%）。PCR 是 2000 年后的主要诊断检测方法。PCR 确认的百日咳博德特氏菌总体中位点流行率为 11%（四分位距（IQR），5-27%），而培养法为 3%（IQR 1-9%），配对血清学为 17%（IQR 3-23%）。平均而言，在同一研究中，培养法比 PCR 法低估流行率 85%（RR=0.15，95%CI，0.10-0.22）。HIV 暴露（RR，1.4（95%CI，1.0-2.0））和感染（RR，2.4（95%CI，1.1-5.1））均与较高的百日咳风险相关。HIV 感染和暴露也与更高的百日咳发病率、更高的住院率和与百日咳相关的死亡率相关。百日咳死亡率和病死率分别为 0.8%（95%CI，0.4-1.4%）和 6.5%（95%CI，4.0-9.5%）。大多数死亡发生在不到 6 个月大的婴儿中。
尽管广泛使用了百日咳疫苗，但过去 30 年来，中低收入国家的百日咳流行率仍然很高。需要增加对基于 PCR 的诊断确认的获取，以改善监测。中低收入国家的疾病控制措施必须考虑到与 HIV 感染和暴露相关的持续婴儿高死亡率和疾病负担增加。
