Background

Pregnant women and infants are known as high risk groups for influenza. WHO recommend pregnant women be vaccinated with inactivated influenza vaccine. In Japan, some municipalities started to give subsidy to encourage pregnant women to receive a shot on their own accord, which has made the introduction of seasonal antepartum maternal vaccination program (AMVP) into the routine vaccination list a current topic in health policy and has raised the need to evaluate the value for money of such possibility.

Methods

We conducted a cost-effectiveness analysis to evaluate the efficiency of conducting AMVP in Japan. A decision tree model was adopted taking into consideration the duration of single-year vaccine effectiveness for infants and for mothers. The program targeted pregnant women aged 20–49 years old at or over 12 weeks gestation during October 1 through March 30. Estimated probabilities of treatments received due to influenza for pregnant/postpartum women or their infants varied by calendar time, vaccination status, and/or gestational age. Incremental cost-effectiveness ratio (ICER) compared with current no-AMVP from societal perspective was calculated. Transition probabilities, utility weights to estimate quality-adjusted life year (QALY), and disease treatment costs were either calculated or extracted from literature. Costs per vaccination was assumed at ¥3,529/US$32.1.

Results

AMVP reduces disease treatment costs, while the reduction cannot offset the vaccination cost. Incremental QALYs were at 0.00009, among them 84.2% were from infants. ICER was ¥7,779,356/US$70,721 per QALY gained. One-way sensitivity analyses revealed that vaccine effectiveness for infant and costs per shot were the two main key variables affecting the ICER.

Conclusion

We found that vaccinating pregnant women with influenza vaccine to prevent unvaccinated infants and pregnant/postpartum women from influenza-associated disease in Japan can be cost-effective from societal perspective, under the WHO-suggested “cost-effective” criteria (1–3 times of GDP).

中文翻译：

---

日本怀孕期间接种流感疫苗的成本效益分析

背景

孕妇和婴儿被称为流感的高危人群。世卫组织建议孕妇接种灭活流感疫苗。在日本，一些城市开始提供补贴以鼓励孕妇自行注射，这使得将季节性产前产妇疫苗接种计划（AMVP）引入常规疫苗接种清单已成为卫生政策中的当前话题，并提出了建议。需要评估这种可能性的物有所值。

方法

我们进行了成本效益分析，以评估在日本进行AMVP的效率。采用了决策树模型，其中考虑了婴儿和母亲一年疫苗有效期的持续时间。该计划针对10月1日至3月30日期间妊娠12周或以上的20-49岁孕妇，孕妇/产后妇女或其婴儿因流感而接受治疗的估计概率因日历时间，疫苗接种状况和/而异或胎龄。从社会角度，计算了与当前无AMVP相比的增量成本效益比（ICER）。过渡概率，估计质量调整生命年（QALY）的效用权重以及疾病治疗成本均通过计算或从文献中得出。

结果

AMVP降低了疾病治疗成本，而这种降低不能抵消疫苗接种成本。增量QALY为0.00009，其中84.2％来自婴儿。每获得QALY，ICER为7,779,356日元/ 70,721美元。单向敏感性分析表明，婴儿疫苗的有效性和单次注射费用是影响ICER的两个主要变量。

结论

我们发现，在世界卫生组织建议的“成本效益”标准下，从社会角度出发，在日本为孕妇接种流感疫苗以预防未接种疫苗的婴儿以及孕妇/产后妇女免受流感相关疾病的影响是符合成本效益的（1-3倍） GDP）。