Pillai Anish, Nayak Anuja, Tiwari Deepika, Pillai Pratichi Kadam, Pandita Aakash, Sakharkar Sachin, Balasubramanian Haribalakrishna, Kabra Nandkishor
Surya Hospitals, Mangal Ashirwad Building, Swami Vivekananda Road, Santacruz West, Mumbai 400054, Maharashtra, India.
British Columbia Children's Hospital Research Institute, 938 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada.
Vaccines (Basel). 2023 Mar 17;11(3):693. doi: 10.3390/vaccines11030693.
Since the coronavirus disease (COVID-19) pandemic hit the globe in early 2020, we have steadily gained insight into its pathogenesis; thereby improving surveillance and preventive measures. In contrast to other respiratory viruses, neonates and young children infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have a milder clinical presentation, with only a small proportion needing hospitalization and intensive care support. With the emergence of novel variants and improved testing services, there has been a higher incidence of COVID-19 disease reported among children and neonates. Despite this, the proportion of young children with severe disease has not increased. Key mechanisms that protect young children from severe COVID-19 disease include the placental barrier, differential expression of angiotensin-converting enzyme 2 (ACE-2) receptors, immature immune response, and passive transfer of antibodies via placenta and human milk. Implementing mass vaccination programs has been a major milestone in reducing the global disease burden. However, considering the lower risk of severe COVID-19 illness in young children and the limited evidence about long-term vaccine safety, the risk-benefit balance in children under five years of age is more complex. In this review, we do not support or undermine vaccination of young children but outline current evidence and guidelines, and highlight controversies, knowledge gaps, and ethical issues related to COVID-19 vaccination in young children. Regulatory bodies should consider the individual and community benefits of vaccinating younger children in their local epidemiological setting while planning regional immunization policies.
自2020年初冠状病毒病（COVID-19）大流行席卷全球以来，我们对其发病机制的认识不断深入，从而改进了监测和预防措施。与其他呼吸道病毒不同，感染严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的新生儿和幼儿临床表现较轻，只有一小部分需要住院和重症监护支持。随着新型变种的出现和检测服务的改进，儿童和新生儿中报告的COVID-19发病率有所上升。尽管如此，患有严重疾病的幼儿比例并未增加。保护幼儿免受严重COVID-19疾病影响的关键机制包括胎盘屏障、血管紧张素转换酶2（ACE-2）受体的差异表达、不成熟的免疫反应以及抗体通过胎盘和母乳的被动转移。实施大规模疫苗接种计划是减轻全球疾病负担的一个重要里程碑。然而，考虑到幼儿患严重COVID-19疾病的风险较低以及关于长期疫苗安全性的证据有限，五岁以下儿童的风险效益平衡更为复杂。在本综述中，我们既不支持也不反对幼儿接种疫苗，而是概述当前的证据和指南，并强调与幼儿COVID-19疫苗接种相关的争议、知识空白和伦理问题。监管机构在制定区域免疫政策时，应考虑在当地流行病学背景下为年幼儿童接种疫苗对个人和社区的益处。
