Safety of BCG vaccination and revaccination in healthcare workers

BCG vaccination and revaccination are increasingly being considered for the protection of adolescents and adults against tuberculosis and, more broadly, for the off-target protective immunological effects against other infectious and noninfectious diseases. Within an international randomized controlled trial of BCG vaccination in healthcare workers (the BRACE trial), we evaluated the incidence of local and serious adverse events, as well as the impact of previous BCG vaccination on local injection site reactions (BCG revaccination). Prospectively collected data from 99% (5351/5393) of participants in Australia, Brazil, Spain, The Netherlands and the UK was available for analysis. Most BCG recipients experienced the expected self-limiting local injection site reactions (pain, tenderness, erythema, swelling). BCG injection site itch was an additional common initial local symptom reported in 49% of BCG recipients. Compared to BCG vaccination in BCG-naïve individuals, BCG revaccination was associated with increased frequency of mild injection site reactions, as well as earlier onset and shorter duration of erythema and swelling, which were generally self-limiting. Injection site abscess and regional lymphadenopathy were the most common adverse events and had a benign course. Self-resolution occurred within a month in 80% of abscess cases and 100% of lymphadenopathy cases. At a time when BCG is being increasingly considered for its off-target effects, our findings indicate that BCG vaccination and revaccination have an acceptable safety profile in adults.卡介苗（BCG）接种与复种正日益被考虑用于青少年和成人的结核病防护，更广泛地说，还可用于针对其他感染性与非感染性疾病的非靶标保护性免疫效应。在一项针对医护人员的卡介苗接种国际随机对照试验（BRACE试验）中，本研究评估了局部与严重不良事件的发生率，同时探究了既往卡介苗接种对局部注射部位反应的影响（即卡介苗复种）。本研究纳入来自澳大利亚、巴西、西班牙、荷兰与英国的受试者，其中99%（5351/5393）的前瞻性收集数据可用于分析。多数卡介苗接种者会出现预期的自限性局部注射部位反应，包括疼痛、压痛、红斑与肿胀。卡介苗接种部位瘙痒是另一项常见的初始局部症状，在49%的卡介苗接种者中被报道。与未接种过卡介苗的个体的卡介苗初次接种相比，卡介苗复种会导致轻度注射部位反应的发生频率升高，同时红斑与肿胀的发作更早、持续时间更短，且上述反应通常均为自限性。注射部位脓肿与区域淋巴结病变是最常见的不良事件，且病程均为良性。80%的脓肿病例与全部淋巴结病变病例可在1个月内自行消退。在卡介苗因其非靶标效应日益受到关注的当下，本研究结果表明，卡介苗接种与复种在成人群体中均具有可接受的安全性。