Department of Paediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Karachi, Sindh 74800, Pakistan.
Department of Paediatrics and Child Health, Aga Khan University Hospital, National Stadium Rd, Karachi, Sindh 74800, Pakistan; The Kirby Institute, University of New South Wales, Level 6, Wallace Wurth Building, High Street, Kensington, Sydney, NSW 2052, Australia.
Vaccine. 2022 Aug 26;40(36):5391-5398. doi: 10.1016/j.vaccine.2022.06.072. Epub 2022 Aug 6.
Typhoid conjugate vaccine (TCV) has recently been introduced in the expanded program for immunization (EPI) in Pakistan. Before its introduction in routine immunization, a onetime catchup campaign among children 9 months to 15 years old was conducted in November 2019. We performed field evaluation of TCV against culture confirmed Salmonella Typhi (S. Typhi) among 9 months to 15 years old children during the catch up campaign in Karachi and Hyderabad.
A rapid assessment of blood culture confirmed S. Typhi was performed. Age eligible cases of culture confirmed S. Typhi were identified from the laboratory networks of Aga Khan University Hospital Karachi and Hyderabad, Kharadar General Hospital Karachi, and Liaqat University of Medical & Health Sciences (LUMHS) Hyderabad. Information on sociodemographic, typhoid vaccination history and antimicrobial resistance was collected using a structured questionnaire. Patient medical records and lab reports were also reviewed to collect information on diagnosis and antimicrobial susceptibility information. Information about the population vaccination coverage during catch-up campaign was obtained from the provincial EPI office. Field performance of TCV in catchup campaign was measured by calculating the effectiveness using rapid screening method which is less resource-intensive technique of calculating vaccine effectiveness (VE).
Overall, 968 culture confirmed typhoid cases were enrolled. Among them, 82% (793/968) were from Karachi and 18% (175/968) from Hyderabad. The average age of the participants was 5.68 years, and 54% (523/968) were male. 6% (62/968) of the culture confirmed S. Typhi cases were multidrug resistant (MDR), and 61% (586/968) were extensively drug resistant (XDR). The VE using the TCV coverage data provided by EPI was 98%.
TCV is effective against culture confirmed S. Typhi among children aged 9 months to 15 years in the catch-up campaign setting. While typhoid vaccination can significantly decrease the burden of typhoid disease, improvements in sanitation and hygiene are necessary for the prevention of spread of enteric fever. Longer term follow up will be needed to assess the duration of protection and requirement for booster doses of TCV.
伤寒结合疫苗（TCV）最近已在巴基斯坦扩大免疫规划（EPI）中推出。在常规免疫接种之前，于 2019 年 11 月在 9 个月至 15 岁的儿童中开展了一次一次性补种运动。我们在卡拉奇和海得拉巴的补种运动期间，对 TCV 针对 9 个月至 15 岁儿童的文化确认伤寒沙门氏菌（S. Typhi）进行了现场评估。
对血液培养确认的 S. Typhi 进行了快速评估。从卡拉奇阿迦汗大学医院、海得拉巴卡拉达尔综合医院、卡拉奇卡哈尔达尔综合医院和海得拉巴利亚卡特医科大学（LUMHS）的实验室网络中确定了文化确认的 S. Typhi 的年龄合格病例。使用结构化问卷收集与社会人口统计学、伤寒疫苗接种史和抗微生物药物耐药性相关的信息。还审查了患者病历和实验室报告，以收集有关诊断和抗微生物药物敏感性的信息。从省级 EPI 办公室获得了关于补种运动期间人群疫苗接种覆盖率的信息。使用快速筛查方法（一种资源密集度较低的计算疫苗有效性的技术）计算疫苗有效性（VE），以衡量 TCV 在补种运动中的现场表现。
总体而言，共纳入了 968 例文化确认的伤寒病例。其中，82%（793/968）来自卡拉奇，18%（175/968）来自海得拉巴。参与者的平均年龄为 5.68 岁，54%（523/968）为男性。6%（62/968）的文化确认 S. Typhi 病例为多药耐药（MDR），61%（586/968）为广泛耐药（XDR）。使用 EPI 提供的 TCV 覆盖率数据计算的 VE 为 98%。
在补种运动中，TCV 对 9 个月至 15 岁儿童的文化确认 S. Typhi 有效。虽然伤寒疫苗接种可以显著降低伤寒疾病的负担，但改善卫生和环境卫生对于预防肠热病的传播是必要的。需要进行更长期的随访，以评估 TCV 的保护持续时间和加强剂量的需求。
