相對成人而言，兒童及青少年感染新冠肺炎(COVID-19)的症狀雖然比較輕微，感染後仍有可能出現重症如兒童多系統發炎症候群，或產生長期的併發症如急性感染後徵候群。兒童及青少年接種COVID-19疫苗可預防其住院或得到重症及併發症、減少COVID-19病毒變異與傳播及儘快回復正常生活。多數研究及持續的安全監測證實核糖核酸疫苗對兒童及青少年具安全性，接種後產生心肌炎／心包膜炎的嚴重副作用較少見，且大多數病人經醫療照護後皆痊癒。先前因有對抗COVID-19的高強度防疫措施及疫苗，大大減少了其他傳染病的案例，然而這也導致免疫負債的產生，可能會導致被壓抑的傳染病反撲。在與COVID-19共存的時代，防疫措施將大幅度的解封，若進入秋冬季節，流感病毒勢必開始活躍，有可能與新冠病毒造成雙重流行。因此，除鼓勵兒童及青少年維持良好衛生習慣，接種常規疫苗（包含COVID-19疫苗及流感疫苗）是減少免疫負債及雙重流行衝擊最佳的方法。

Although the severity of COVID-19 infection is lower in children and adolescents than in adults, children and adolescents are encouraged to receive vaccination to prevent hospitalization and complications, such as multisystemic inflammatory syndrome and post-COVID conditions, reduce the spread of COVID-19, prevent the emergence of other variants, and restore a normal life. COVID-19 mRNA vaccines are suggested to be safe for children and teenagers. Severe events, such as myocarditis and pericarditis, after pediatric COVID-19 mRNA vaccination are rare. Most patients fully recover after management. Strict public health nonpharmaceutical interventions and vaccination program disturbances may cause an immunity debt in children. Therefore, vaccine-preventable diseases may reemerge after the lifting of COVID-19 mitigation measures. Twindemic may occur in the next influenza season due to the coexistence of influenza and SARS-CoV-2 viruses. In addition to maintaining good hygiene, emphasizing and encouraging pediatric routine immunization, including COVID-19 and influenza vaccination, are the most favorable methods for overcoming immunity debt and preventing twindemic.