In mid-December 2019, a disease caused by infection with severe acute respiratory syndrome coronavirus-2, which began in Wuhan, China, has spread throughout the country and many countries around the world. The number of children with coronavirus disease-2019 (COVID-19) has also increased significantly. Although information regarding the epidemiology of COVID-19 in children has accumulated, relevant comprehensive reports are lacking. The present article reviews the epidemiological characteristics of COVID-19 in children.

Aim Vaccines are vital to ending the COVID‐19 pandemic and we reviewed the data on vaccinating children, and including them in clinical trials, as most of the activity has focused on adults. Methods English and Chinese databases, including PubMed, Elsevier Scopus, Web of Science, CNKI and CQVIP were searched, along with websites such as the World Health Organization and the University of Oxford. Results We identified 44 papers and 16 news items about vaccinating children against the virus, published from 10 February 2020 to 14 July 2021. Child vaccination has been slow and only a few countries have included children in Phase II or III clinical trials. The data on children were much more limited than on adults, but most children were asymptomatic or had mild symptoms and some deaths had been recorded. More clinical trials are needed to assess the safety and efficacy of vaccinating children, as higher vaccination levels can help to build up herd immunity. The percentage of parents willing to vaccinate their children against the virus ranged from 48.2% to 72.6%, with much lower rates for letting them participate in clinical trials. Conclusion Vaccines should be offered to children as soon as their safety and efficacy are established.

Since December 2019, corona virus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic, posing a huge threat to human health, and the current epidemic prevention situation is still severe. Hematological parameters directly reflect the damage of SARS-CoV-2 to human blood cells, which can better assess the severity and prognosis of patients infected with COVID-19, but hematological parameters have some differences between adults and children. This article comprehensively reviews the differences in hematological parameters between adults and children after SARS-CoV-2 infection, and provides a reference for the diagnosis and treatment of COVID-19.