Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan.
Infectious Diseases Research Laboratory (IDRL), Department of Pediatrics and Child Health, Aga Khan University, Karachi, Pakistan.
Vaccine. 2024 Oct 3;42(23):126238. doi: 10.1016/j.vaccine.2024.126238. Epub 2024 Aug 20.
In early 2021, the 10-valent Pneumococcal conjugate vaccine (PCV10) was replaced with 13-valent (PCV13) by the federal directorate of immunization (FDI), Pakistan. We assessed the impact of a higher valent vaccine, PCV13, on the serotype distribution of nasopharyngeal carriage in rural Pakistan.
Children <2 years were randomly selected from two rural union councils of Matiari, Sindh in Pakistan between September-October,2022. Clinical, sociodemographic and vaccination histories were recorded. Nasopharyngeal swabs were collected and processed at Infectious Disease Research Laboratory, Aga Khan University, Karachi. Whole genome sequencing was performed on the culture positive isolates.
Of the 200 children enrolled, pneumococcus was detected in 140(70 %) isolates. Majority of age-eligible children (60.1 %,110/183) received 3 PCV13 doses. PCV10 carriage declined from 13.2 %(78/590) in 2017/18 to 7.2 % (10/140) in 2022, additional PCV13 serotypes (3, 6A/6C and 19A) decreased from 18.5 %(109/590) to 11.4 %(16/140) while non-PCV13 serotypes increased from 68.3 %(403/590) to 81.4 %(114/140). There were 88.5 %(n = 124), 80.7 %(n = 113), 55.0 %(n = 77), and 46.0 %(n = 65) isolates predicted to be resistant to cotrimoxazole, penicillin(meningitis cut-off), tetracycline, and erythromycin respectively.
Replacing PCV10 with PCV13 rapidly decreased prevalence of PCV13 carriage among vaccinated children in Matiari, Pakistan. Vaccine-driven selection pressure may have been responsible for the increase of non-PCV13 serotypes.
2021 年初，巴基斯坦联邦免疫署（FDI）用 13 价肺炎球菌结合疫苗（PCV13）替代了 10 价肺炎球菌结合疫苗（PCV10）。我们评估了更高价疫苗 PCV13 对巴基斯坦农村地区鼻咽携带的血清型分布的影响。
2022 年 9 月至 10 月，在巴基斯坦信德省马蒂亚里的两个农村联盟委员会中随机选择 <2 岁的儿童。记录临床、社会人口统计学和疫苗接种史。在卡拉奇的阿迦汗大学传染病研究实验室采集鼻咽拭子并进行处理。对培养阳性分离株进行全基因组测序。
在 200 名入组儿童中，140 名（70%）分离株检测到肺炎球菌。大多数符合年龄条件的儿童（60.1%，110/183）接受了 3 剂 PCV13 疫苗。2017/18 年 PCV10 携带率为 13.2%（78/590），2022 年降至 7.2%（10/140），额外的 PCV13 血清型（3、6A/6C 和 19A）从 18.5%（109/590）降至 11.4%（16/140），而非 PCV13 血清型从 68.3%（403/590）增至 81.4%（114/140）。分别有 88.5%（n=124）、80.7%（n=113）、55.0%（n=77）和 46.0%（n=65）的分离株被预测对复方新诺明、青霉素（脑膜炎截断值）、四环素和红霉素耐药。
在马蒂亚里，巴基斯坦用 PCV13 替代 PCV10 后，疫苗接种儿童中 PCV13 携带率迅速下降。疫苗驱动的选择压力可能是导致非 PCV13 血清型增加的原因。
