Nouh Khaliif, Haga Abdirizak, Sumaili Kyandindi, Farid Muhammad, Alin Mohamed, Shube Mukhtar, Abshir Abdirizak, Hiirad Mohamed, Ahmed Muhyadeen, Bile Ahmed
Federal Ministry of Health (FMoH), Mogadishu, Somalia.
United Nations Children's Fund (UNICEF), Garowe, Somalia.
BMC Glob Public Health. 2024 Mar 6;2(1):16. doi: 10.1186/s44263-024-00044-7.
Global efforts reduced incidence of polio cases from 350,000 in 1988 to 22 cases in 2022 globally. There have been no wild poliovirus (WPV) cases seen in Somalia since August 2014. However, in 2017, there was a surge in the number of cases of circulating vaccine-derived poliovirus type 2 (cVDPV2), even with different intervention responses using monovalent oral polio vaccine type 2 (mOPV2). This study aimed to assess the use of fractional inactivated polio vaccine (fIPV), a smaller dose of the polio vaccine, equal to 1/5 of a standard dose, as an innovative polio vaccination delivery model, and identify the main opportunities for and challenges to the use of fIPV in the future for vaccinations.
The study used two designs: a quasi-experimental design used to pilot fIPV in five districts and a cross-sectional study using both quantitative and qualitative approaches to collect primary data. A simple random sampling method was used to select 2 out of the 5 pilot districts for household surveys to study 768 participants. Key informant interviews and focus-group discussions were used to collect data from key frontline health workers and health/immunization officials involved in the campaigns. Secondary data from the pilot campaigns were analysed, such as administrative pilot data, lot quality assurance sampling (LQAS) and post-campaign communication assessments.
A total of 131,789 children aged 4-59 months were included for the pilot. Among these, 126,659 (96.1%) and 126,063 (95.6%) children were vaccinated in rounds 1 and 2, respectively. Out of the 768 households assessed, 99.9% had their children vaccinated. Nearly half of the few children who were not vaccinated were reported to be due to the parent of the child not being at home (48%). Ninety-seven percent of the qualitative study interviewees were satisfied with fIPV injection and recommended its use for routine immunization.
The study findings are promising in the use of fIPV in mass campaigns to realize better coverage and global polio eradication. fIPV will potentially be used by policymakers in the design of polio eradication campaigns that integrate the fIPV vaccine into routine or supplementary immunization.
全球的努力使脊髓灰质炎病例的发病率从1988年的35万例降至2022年的全球22例。自2014年8月以来，索马里未出现野生脊髓灰质炎病毒（WPV）病例。然而，2017年，2型循环疫苗衍生脊髓灰质炎病毒（cVDPV2）病例数激增，即便使用了2型单价口服脊髓灰质炎疫苗（mOPV2）进行不同的干预应对措施。本研究旨在评估使用小剂量脊髓灰质炎疫苗——分剂量灭活脊髓灰质炎疫苗（fIPV），其剂量为标准剂量的1/5，作为一种创新的脊髓灰质炎疫苗接种模式，并确定未来使用fIPV进行疫苗接种的主要机遇和挑战。
该研究采用了两种设计：一种准实验设计用于在五个地区试点fIPV，以及一项采用定量和定性方法收集原始数据的横断面研究。使用简单随机抽样方法从5个试点地区中选取2个进行家庭调查，以研究768名参与者。通过关键 informant 访谈和焦点小组讨论，从参与活动的关键一线卫生工作者和卫生/免疫官员那里收集数据。对试点活动的二级数据进行了分析，如行政试点数据、批质量保证抽样（LQAS）和活动后沟通评估。
共有131,789名4至59个月大的儿童纳入试点。其中，分别有126,659名（96.1%）和126,063名（95.6%）儿童在第1轮和第2轮接种了疫苗。在评估的768户家庭中，99.9%的家庭儿童接种了疫苗。据报告，少数未接种疫苗的儿童中，近一半是由于孩子的家长不在家（48%）。定性研究中97%的受访者对fIPV注射感到满意，并建议将其用于常规免疫。
该研究结果表明，在大规模活动中使用fIPV有望实现更好的覆盖率并根除全球脊髓灰质炎。fIPV可能会被政策制定者用于设计将fIPV疫苗纳入常规或补充免疫的脊髓灰质炎根除活动中。
