Secretaria de Estado da Saúde de São Paulo, Coordenadoria de Controle de Doenças, Centro de Vigilância Epidemiológica "Prof. Alexandre Vranjac", Divisão de Imunização, São Paulo, São Paulo, Brazil.
Instituto de Infectologia Emílio Ribas, São Paulo, São Paulo, Brazil.
Rev Inst Med Trop Sao Paulo. 2021 Dec 6;63:e83. doi: 10.1590/S1678-9946202163083. eCollection 2021.
Twenty-seven children aged seven months to 5 years were inadvertently vaccinated with a COVID-19 vaccine, the CoronaVac (Sinovac, China), an inactivated SARS-CoV-2 vaccine, in two different cities of Sao Paulo State, Brazil. After the event, these children were monitored by local pediatricians and serum samples were collected at the first visit and 30 days after vaccination and tested for SARS-CoV-2 S1 serology with Ortho total IgG anti-S1 protein and Cpass, an ACE2 receptor binding domain inhibition assay. Only one child had a mild symptom after vaccination, with no other adverse events documented up to the 30 days follow-up. Of 27 children tested 3-9 days after vaccination, 5 (19%) had positive serology suggesting a previous natural SARS-CoV-2 infection, with all 19 tested on day 30 after vaccination and presenting with positive tests, with an increment of antibody titers in those initially positive. A low Cpass binding inhibition was observed in the first collection in 11 seronegative cases, with high titers among those anti-S1 positive. All children showed an important increase in antibody titers on day 30. The event allowed the documentation of a robust serological response to one dose of CoronaVac in this small population of young children, with no major adverse effects. Although it was an unfortunate accident, this event may contribute with future vaccine strategies in this age group. The data suggest that CoronaVac is safe and immunogenic for children.
27 名 7 个月至 5 岁的儿童在巴西圣保罗州的两个不同城市意外接种了科兴新冠疫苗（克尔来福，中国），这是一种灭活的 SARS-CoV-2 疫苗。事件发生后，这些儿童由当地儿科医生进行监测，并在首次就诊和接种后 30 天采集血清样本，用 Ortho 总 IgG 抗 S1 蛋白和 Cpass 检测 SARS-CoV-2 S1 血清学，这是一种 ACE2 受体结合域抑制测定法。仅有 1 名儿童在接种后出现轻度症状，在 30 天的随访中没有其他不良事件记录。在接种后 3-9 天检测的 27 名儿童中，有 5 名（19%）血清学检测呈阳性，提示之前有过自然感染 SARS-CoV-2，所有 19 名儿童在接种后第 30 天进行检测，结果均呈阳性，最初呈阳性的抗体滴度增加。在 11 例血清阴性病例的首次采集中观察到低 Cpass 结合抑制，在抗 S1 阳性病例中观察到高滴度。所有儿童在第 30 天的抗体滴度都有显著增加。该事件记录了在该小年龄组儿童中接种一剂科兴新冠疫苗产生的强烈血清学反应，没有出现重大不良影响。尽管这是一起不幸的意外，但该事件可能为该年龄段的未来疫苗策略提供依据。数据表明科兴新冠疫苗对儿童是安全且具有免疫原性的。
