Discussion
In the epidemiological study from China, ninety per cent of the
SARS-CoV-2 infected children had mild to moderate
symptoms.3 Younger children, less than 5-year-old,
were more likely to develop a complication.3 Majority
of symptomatic children with COVID-19 presented with upper respiratory
symptomatology.1 There was a lack of data on COVID-19
infection in immunocompromised children. However, the outcome can be
predicted based on the effect of other Human Coronavirus (HCoV)
infection to immunocompromised children. In a retrospective study, both
of the immunocompromised and immunocompetent children with HCoV
infection presented similarly, mainly with fever, cough and sore
throat.4 The severity was identical even with
different strains of HCoV.1,4 However,
immunocompromised children were more likely to develop severe pneumonia
compared to immunocompetent children.4
Morbidity and mortality in the patients with COVID-19 are thought to be
due to hyper-inflammatory state such as cytokine storm
syndrome.5 It is thought that immature and poor
functioning ACE-2 receptor which reduced the SARS-CoV-2 virus affinity
to the receptor, higher level of antibody against respiratory viruses,
the cross protection of childhood immunisation program, and the lack of
coronavirus-specific memory cells have led to reduce direct
cell-mediated attack and inflammation on alveoli and other
organs.3,6 This exaggerated innate immune response was
not seen in the immunocompromised children.2,7 During
the SARS-CoV outbreak in 2002/2003, children with organ transplant had
good outcome.7 Similarly, there was no documented
severe COVID-19 pneumonia among paediatric liver transplant patients in
Italy.7
In contrast to the reported case of COVID-19 positive leukemic child by
Chen et al., our patient was asymptomatic throughout the disease course.
The reported child developed a high-grade fever which progressed into
pneumonia requiring intensive care unit admission.8The severe neutropenia and concomitant influenza A infection might have
contributed to more severe disease in the reported
child.8
In conclusion, this report and other previous cases of COVID-19 in
immunocompromised children revealed that the infection is mild. The
severity may however be worse with concomitant other respiratory virus
infection. Further evidence on the pathogenesis and outcome of
SARS-CoV-2 infection on immunocompromised children are required before
any conclusion can be made.