Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, England, United Kingdom.
Immunisation, Hepatitis and Blood Safety Department, Public Health England, London, England, United Kingdom.
J Infect. 2016 Jul;73(1):28-37. doi: 10.1016/j.jinf.2016.04.012. Epub 2016 Apr 22.
Maternal pertussis immunisation was introduced during the pertussis resurgence in England in 2012 as a temporary measure to protect infants too young to be vaccinated. The programme was shown to be safe and highly effective. However, continuation of maternal vaccination as a routine programme requires a cost-effectiveness analysis.
The estimated prevented disease burden among mothers and their infants was obtained assuming 89% (95% CI: 19%-99%) vaccine efficacy for mothers and 91% (95% CI: 84%-95%) for infants. Future incidence was projected based on the disease rates in 2010-2012, including the four-year cycle of low and high incidence years. Full probabilistic sensitivity analysis was performed for different scenarios.
Assuming a vaccine coverage of 60%, there were 1650 prevented hospitalisations in infants (3.5% discounting, the first 10 years), including 55-60 deaths and ∼20,500 cases among mothers, of which around 1800 would be severe. The annual costs of the programme are £7.3 million assuming a price of £10 per dose and £9.4 million assuming £15 per dose. Using discounting of 3.5%, a 200 year time horizon and a price of £10 per dose (+£7.5 administration costs) only 25% of the iterations were below £30,000 per QALY. Using a 35% higher incidence resulted in 88% of the scenarios below this threshold. Assuming that the incidence remains at the level at the height of 2012, then the programme would be highly cost effective, with an ICER of £16,865 (£12,209-£25,976; price of £10 and 3.5%/3.5% discounting).
Maternal vaccination is effective in preventing severe illness and deaths in infants but the cost-effectiveness of the programme is highly dependent on future incidence which is necessarily uncertain. However, the duration and magnitude of protection against transmission afforded by the current acellular vaccines is also uncertain as are the associated effects on future herd immunity. The direct protection offered by the maternal dose provides the only certain way of protecting vulnerable infants from birth.
2012 年英国百日咳疫情爆发后，开始为母亲接种百白破疫苗，作为保护尚未到接种年龄婴儿的临时措施。该疫苗已被证明安全且非常有效。然而，要将母亲接种疫苗作为常规计划继续下去，则需要进行成本效益分析。
假设母亲的疫苗效力为 89%（95%CI：19%-99%），婴儿的疫苗效力为 91%（95%CI：84%-95%），从而得出预防母婴疾病的估计负担。根据 2010-2012 年的疾病发生率，包括四年一次的低发年和高发年，预测未来的发病率。对不同方案进行了全面的概率敏感性分析。
假设疫苗覆盖率为 60%，则可预防 1650 名婴儿住院（不考虑前 10 年的 3.5%折扣），包括 55-60 例死亡和大约 20500 例母亲病例，其中约 1800 例为重症。如果每剂价格为 10 英镑，该计划的年度成本为 730 万英镑；如果每剂价格为 15 英镑，则为 940 万英镑。使用 3.5%的折扣率、200 年的时间范围和每剂 10 英镑的价格（+7.5 英镑的管理费用），只有 25%的迭代结果低于每 QALY（质量调整生命年）3 万英镑。使用更高的发病率 35%，则 88%的方案低于该阈值。如果发病率保持在 2012 年高峰期的水平，则该计划将具有很高的成本效益，其 ICER（增量成本效益比）为 16865 英镑（12209 英镑至 25976 英镑；价格为 10 英镑，3.5%/3.5%的折扣率）。
母亲接种疫苗可有效预防婴儿的严重疾病和死亡，但该计划的成本效益高度依赖于未来的发病率，而未来的发病率必然是不确定的。然而，目前使用的无细胞疫苗提供的保护母婴免受疾病传播的持续时间和程度也存在不确定性，以及对未来群体免疫的影响也存在不确定性。母亲剂量提供的直接保护是保护脆弱婴儿免受疾病的唯一可靠方法。
