. 2022 Jan 19;64(1):90–107. doi: 10.1007/s12016-022-08921-5

Table 2.

Risk factors and their correlations with the infection and severity of COVID-19 in children

Risk factors for the infection and severity of COVID-19	Correlations
Age (infants and/or older adolescents)	• Immaturity of the immune system [47] • Lower likelihood of wearing face masks and the subsequent high viral load [47] • Minimal or lower pre-existing immunity to help protect against severe lower respiratory illness due to SARS-CoV-2 [48]
Pre-existing comorbidities	• Weaker immune defense [5–7] • Sustained lower level of immunity status reduces the resistance to virus infection [8, 30] • Previous organ damage promotes the progression of COVID-19 [13]

Risk factors for the infection and severity of COVID-19

Correlations

Age (infants and/or older adolescents)

• Immaturity of the immune system [47]

• Lower likelihood of wearing face masks and the subsequent high viral load [47]

• Minimal or lower pre-existing immunity to help protect against severe lower respiratory illness due to SARS-CoV-2 [48]

Pre-existing comorbidities

• Weaker immune defense [5–7]

• Sustained lower level of immunity status reduces the resistance to virus infection [8, 30]

• Previous organ damage promotes the progression of COVID-19 [13]

ACE2 angiotensin-converting enzyme, IL interleukin, IFN interferon, TNF tumor necrosis factor