HSCT Program, Amaral Carvalho Foundation, Jahu, Brazil.
Núcleo de Apoio ao Pesquisador, Hospital do Amor, Barretos, Brazil.
Transpl Infect Dis. 2020 Jun;22(3):e13258. doi: 10.1111/tid.13258. Epub 2020 Feb 24.
Hepatitis A virus (HAV) infection is highly prevalent in developing countries. In countries experiencing a shift from intermediate/high endemicity to low endemicity, the World Health Organization recommends the incorporation of HAV vaccine into the national vaccination calendar for children aged ≥1 year. Since HAV antibodies wane over time, most HSCT revaccination guidelines advise vaccination as optional, following the country recommendation. However, no study has evaluated the serological response to HAV vaccine in allogeneic HSCT recipients.
We conducted a prospective study in 46 HSCT recipients who received two doses of inactivated HAV vaccine. Blood samples were taken before vaccination to determine HAV prevalence rates, and before and 4-6 weeks after the second dose. Specific anti-HAV antibodies were detected by a competitive commercial enzyme immune assay.
Patients received the first dose of vaccine at a median of 332.5 (120-4134) days after HSCT. Median absolute lymphocyte count at vaccination was 1947 (696-12 500)/mm . The seroprevalence rate was 93.5% at inclusion. Although safe and well tolerated, the serological response to HAV vaccine in susceptible patients was poor (33%), and no boost effect was observed in seropositive patients.
In areas with intermediate/high seroprevalence of HAV, serology should be recommended prior to referral to vaccination. The mechanisms of antibody interference and how to overcome T-cell function deficiency need to be better understood in transplant populations receiving HAV vaccine. Alternative schedules of HAV vaccination should be evaluated in prospective trials.
甲型肝炎病毒 (HAV) 感染在发展中国家极为普遍。在从中度/高度流行向低度流行转变的国家，世界卫生组织建议将 HAV 疫苗纳入国家儿童免疫接种规划，年龄≥1 岁。由于 HAV 抗体随时间推移而衰减，大多数异基因造血干细胞移植（HSCT）再接种指南建议根据国家建议，将接种疫苗作为可选方案。然而，尚无研究评估 HAV 疫苗在异基因 HSCT 受者中的血清学反应。
我们对 46 例接受两剂灭活 HAV 疫苗的 HSCT 受者进行了前瞻性研究。在接种疫苗前采血以确定 HAV 流行率，并在接种前和第二剂接种后 4-6 周采血。采用竞争商业酶免疫测定法检测特定的抗-HAV 抗体。
患者在 HSCT 后中位数为 332.5（120-4134）天接受第一剂疫苗。接种疫苗时的中位数绝对淋巴细胞计数为 1947（696-12500）/mm³。纳入时的血清流行率为 93.5%。尽管疫苗接种安全且耐受良好，但易感患者对 HAV 疫苗的血清学反应较差（33%），且在血清阳性患者中未观察到增强效应。
在 HAV 中度/高度流行的地区，在转诊接种疫苗之前，应推荐进行血清学检测。在接受 HAV 疫苗的移植人群中，需要更好地了解抗体干扰的机制以及如何克服 T 细胞功能缺陷。需要在前瞻性试验中评估 HAV 疫苗接种的替代方案。
