GSK, Panama.
Instituto de Investigaciones Científicas y Servicios de Alta Tecnología de Panama, Panama City, Panama.
Vaccine. 2021 Jan 3;39(1):26-34. doi: 10.1016/j.vaccine.2020.11.030. Epub 2020 Nov 22.
Hepatitis A virus (HAV) remains a global public health concern, which is potentially growing in Latin America, due to an expected shift from high to intermediate endemicity levels. The use of HAV vaccines in pediatric national immunization programs (NIPs), either as a 2-dose or a 1-dose schedule, has been explored in Latin American countries; however, evidence demonstrating long-term protection in this population is limited in the region. We evaluated long-term antibody persistence following a 1-dose partial series and the recommended 2-dose schedule used in Panama's pediatric NIP.
Two independent cross-sectional serological surveys were conducted at year 8 (Y8) and Y10 following vaccination under the NIP with 1 or 2 doses of an inactivated HAV vaccine (Havrix, GSK). Seropositivity (anti-HAV antibody concentration ≥ 15 mIU/mL) rates and antibody geometric mean concentrations (GMCs) were assessed at each serosurvey. Non-inferiority of 1 dose versus 2 doses was also explored.
This study (NCT02712359) included 600 and 599 children at Y8 and Y10 post-vaccination, respectively. Seropositivity rates were 74.3% (95% confidence interval [CI]: 69.0; 79.2) and 97.7% (95% CI: 95.3; 99.1) at Y8 and 71.9% (95% CI: 66.4; 76.9) and 96.3% (95% CI: 93.5; 98.2) at Y10, in the 1-dose and 2-dose groups, respectively. Antibody GMCs were lower in the 1-dose versus the 2-dose group in both surveys. Non-inferiority was not demonstrated since the lower limit of the 2-sided 95% CI for the between-group difference in seropositivity rates (1-dose minus 2-dose) was < -10%.
Anti-HAV antibody persistence was observed in lower percentages of children receiving 1 dose versus 2 doses of Havrix, at 8 and 10 years post-vaccination in Panama. Further investigations are needed to confirm antibody persistence and conclude on the protection afforded beyond 10 years in the pediatric population in Latin America.
甲型肝炎病毒（HAV）仍然是全球公共卫生关注的问题，由于预计其流行程度将从中高度转变为中度，因此在拉丁美洲地区呈上升趋势。在拉丁美洲国家，已经探索了在儿童国家免疫规划（NIP）中使用 HAV 疫苗，无论是两剂还是一剂方案；然而，该地区的证据表明，这种人群的长期保护作用有限。我们评估了巴拿马儿童 NIP 中使用的一剂部分系列和推荐的两剂方案接种后的长期抗体持久性。
在 NIP 下接种一剂或两剂灭活 HAV 疫苗（Havrix，GSK）后，分别在第 8 年（Y8）和第 10 年（Y10）进行了两项独立的横断面血清学调查。在每次血清学调查中评估了血清阳性率（抗-HAV 抗体浓度≥15 mIU/mL）和抗体几何平均浓度（GMC）。还探讨了一剂与两剂的非劣效性。
这项研究（NCT02712359）分别在接种疫苗后第 8 年和第 10 年纳入了 600 名和 599 名儿童。在 Y8 和 Y10 时，血清阳性率分别为 74.3%（95%置信区间[CI]：69.0；79.2）和 97.7%（95%CI：95.3；99.1），在 1 剂量组和 2 剂量组中分别为 71.9%（95%CI：66.4；76.9）和 96.3%（95%CI：93.5；98.2）。在两次调查中，一剂组的抗体 GMC 均低于两剂组。由于组间差异（一剂减去两剂）的双侧 95%CI 下限< -10%，因此未证明非劣效性。
在巴拿马，接种 Havrix 后 8 年和 10 年，接受一剂的儿童与接受两剂的儿童相比，抗-HAV 抗体的持久性较低。需要进一步研究以确认抗体持久性，并确定在拉丁美洲儿童人群中 10 年以上的保护作用。
