This case–control study investigated immune thrombocytopenic purpura (ITP) risk following live, inactivated, and simultaneous vaccination, with a focus on infants aged < 2 years. We matched case patients with ITP to one or two control patients with other diseases by institution, hospital visit timing, sex, and age. We calculated McNemar’s pairwise odds ratios (ORs [95% confidence interval]) with 114 case–control pairs. The case group had 27 (44%) males and 22 (35%) infants, and the control group included 49 (43%) males and 42 (37%) infants. For all age groups, the McNemar’s OR for ITP occurrence was 1.80 (0.54–6.84, p = 0.64) for all vaccines. Among infants, these were 1.50 (0.17–18.0, p = 0.50) for all vaccines, 2.00 (0.29–22.1, p = 0.67) for live vaccines, and 1.00 (0.01–78.5, p = 0.50) for inactivated vaccines. Sex-adjusted common ORs for simultaneous vaccination were 1.52 (0.45–5.21, p = 0.71) for all vaccines, 1.83 (0.44–7.59, p = 0.40) for inactivated vaccines only, and 1.36 (0.29–6.30, p = 0.69) for mixed live and inactivated vaccines. In infants, these were 1.95 (0.44–8.72, p = 0.38), 1.41 (0.29–6.94, p = 0.67) and 2.85 (0.43–18.9, p = 0.28), respectively. These limited data suggest no significant ITP risk following vaccinations or simultaneous vaccination in any age group, including infants.

本病例对照研究调查了活疫苗、灭活疫苗和同时接种疫苗后的免疫性血小板减少性紫癜 (ITP) 风险，重点关注 2 岁以下的婴儿。我们按机构、医院就诊时间、性别和年龄将 ITP 病例患者与一或两名患有其他疾病的对照患者进行匹配。我们用 114 个病例-对照对计算了 McNemar 的成对优势比（ORs [95% 置信区间]）。病例组有27名男性（44%）和22名（35%）婴儿，对照组包括49名（43%）男性和42名（37%）婴儿。对于所有年龄组，所有疫苗的 ITP 发生的 McNemar 的 OR 为 1.80（0.54-6.84，p  = 0.64）。在婴儿中，所有疫苗为 1.50 (0.17–18.0, p  = 0.50)，2.00 (0.29–22.1, p = 0.67) 用于活疫苗，1.00 (0.01–78.5, p  = 0.50) 用于灭活疫苗。所有疫苗的同时接种的经性别调整的常见 OR 为 1.52（0.45-5.21，p  = 0.71），仅灭活疫苗为 1.83（0.44-7.59，p  = 0.40），对于所有疫苗为 1.36（0.29-6.30，p  = 0.69）混合活疫苗和灭活疫苗。在婴儿中，这些分别为 1.95 (0.44–8.72, p  = 0.38)、1.41 (0.29–6.94, p  = 0.67) 和 2.85 (0.43–18.9, p  = 0.28)。这些有限的数据表明在任何年龄组（包括婴儿）接种疫苗或同时接种疫苗后没有显着的 ITP 风险。