Forecasting demand for maternal influenza immunization in low- and lower-middle-income countries

Immunization of pregnant women against seasonal influenza remains limited in low- and lower-middle-income countries despite being recommended by the World Health Organization (WHO). The WHO/PATH Maternal Influenza Immunization Project was created to identify and address obstacles to delivering influenza vaccines to pregnant women in low resource setting. To gain a better understanding of potential demand from this target group, we developed a model simulating pregnant women populations eligible for vaccination during antenatal care (ANC) services in all low- and lower-middle-income countries. We assessed potential vaccine demand in the context of both seasonal and year-round vaccination strategies and identified the ways that immunization programs may be affected by availability gaps in supply linked to current vaccine production cycles and shelf life duration. Results of our analysis, which includes 54 eligible countries in 2015 for New Vaccine Support from Gavi, the Vaccine Alliance, suggest the demand for influenza vaccines could be 7.7 to 16.0 million doses in 2020, and 27.0 to 61.7 million doses by 2029. If current trends in production capacity and actual production of seasonal influenza vaccines were to continue, global vaccine supply would be sufficient to meet this additional demand—although a majority of countries would face implementation issues linked to timing of supply.

尽管世界卫生组织（World Health Organization, WHO）已推荐针对孕妇的季节性流感免疫接种方案，但在低收入及中低收入国家中，孕妇流感免疫的覆盖率依然有限。为识别并解决资源受限环境下向孕妇接种流感疫苗的各类障碍，世界卫生组织/PATH孕产妇流感免疫项目（WHO/PATH Maternal Influenza Immunization Project）正式启动。为更深入地了解该目标群体的潜在接种需求，我们针对所有低收入及中低收入国家，构建了可模拟在产前保健（Antenatal Care, ANC）服务期间符合接种条件的孕妇人群的模型。我们分别针对季节性接种与全年接种两种策略场景，评估了潜在的疫苗需求量，并明确了当前疫苗生产周期与保质期相关的供应缺口可能对免疫规划项目产生的影响路径。本次分析纳入了2015年符合全球疫苗免疫联盟（Gavi, the Vaccine Alliance）新疫苗支持计划资格的54个国家，分析结果显示，2020年流感疫苗的潜在需求量可达770万至1600万剂，到2029年这一数字将增至2700万至6170万剂。若当前季节性流感疫苗的产能与实际生产趋势持续下去，全球疫苗供应将足以满足这一新增需求——尽管多数国家仍将面临与供应时机相关的实施难题。