pone.0330281.t003 -

IntroductionDespite intensified global efforts to enhance immunization coverage, one in five children continue to miss out on life-saving vaccines, leaving them vulnerable to a range of vaccine-preventable diseases. In 2022, 14.3 million children failed to receive even a single dose of the pentavalent vaccine (Penta-1) by their first birthday, classified as “zero-dose penta”. Additionally, some children have not received any vaccinations at all and have had no contact with healthcare services—these are referred to as “never-immunized” children. Collectively, both groups—zero-dose penta and never-immunized children—are termed “true zero-dose” to emphasize the critical need for targeted interventions that ensure no child is left behind in immunization efforts.MethodsWe conducted a household (HH) survey from August 10 to December 19, 2022, in Kashmore and Sujawal, two districts in Sindh, Pakistan, with low immunization coverage. The survey targeted children aged 12−23 months who had not received the Penta-1 vaccine by their first birthday. Our study aimed to determine the community-based prevalence of zero-dose penta and never-immunized children, compare their sociodemographic characteristics and immunization histories, and identify predictors of these outcomes.ResultsOf the 2,091 children surveyed, 497 (23.8%) were zero-dose penta, and 587 (28.1%) were never-immunized. Together, these groups constitute 51.9% of the survey population, referred to as ‘true zero-dose’. The remaining 1,007 (48.1%) were either fully or partially immunized. Multivariate analysis indicated that absence of antenatal care (ANC) significantly increased the risk of children being classified as zero-dose penta (RRR = 1.68; 95% CI: 1.04–2.72; p ConclusionDespite global efforts for achieving universal immunization, half of the surveyed children remained true zero-dose, highlighting significant gaps in the ability of immunization programs to reach underserved communities. To address this issue, it is essential to enhance ANC coverage and leverage frontline health workers (FHWs) to identify and engage with clusters of zero-dose children effectively. These measures will ensure that no child is left behind, advancing health equity and safeguarding future generations.## 引言 尽管全球已加大力度提升免疫接种覆盖率，但仍有五分之一的儿童未能获得救命疫苗，易罹患多种可通过疫苗预防的疾病。2022年，有1430万名儿童在满1周岁前未接种任何一剂五联疫苗（pentavalent vaccine, Penta-1），这类儿童被归类为“零剂次五联疫苗儿童”。此外，部分儿童从未接种任何疫苗，且未接触过医疗服务，这类儿童被称为“从未接种疫苗儿童”。综上，零剂次五联疫苗儿童与从未接种疫苗儿童这两类群体，被统称为“真正零剂次接种儿童”，以凸显实施针对性干预措施的迫切性，确保免疫接种工作不落任何一名儿童。 ## 方法 本研究于2022年8月10日至12月19日，在巴基斯坦信德省（Sindh）免疫接种覆盖率较低的卡什莫尔（Kashmore）与苏贾瓦尔（Sujawal）两个县区开展家庭（household, HH）调查。本次调查的研究对象为满1周岁前未接种Penta-1疫苗的12~23月龄儿童。本研究旨在明确零剂次五联疫苗儿童与从未接种疫苗儿童的社区流行率，对比两类人群的社会人口学特征与免疫接种史，并识别上述结局的影响因素。 ## 结果 本次共调查2091名儿童，其中497名（23.8%）为零剂次五联疫苗儿童，587名（28.1%）为从未接种疫苗儿童。上述两类群体合计占调查人群的51.9%，即“真正零剂次接种儿童”。剩余1007名（48.1%）儿童完成了全程或部分免疫接种。多因素分析结果显示，未接受产前保健（antenatal care, ANC）会显著提升儿童被归类为零剂次五联疫苗儿童的风险（相对风险比RRR = 1.68；95%置信区间CI: 1.04–2.72；P）。 ## 结论 尽管全球已为实现全民免疫接种付出诸多努力，但仍有半数受访儿童属于真正零剂次接种群体，这凸显出免疫规划项目在覆盖服务不足社区方面存在显著短板。为解决这一问题，需提升产前保健覆盖率，并依托一线卫生工作者（frontline health workers, FHWs）有效识别并对接聚集性的零剂次接种儿童群体。这些举措将确保不落任何一名儿童，推进健康公平并守护后代健康。