The goal of the present study was to assess the causes of death in children with COVID-19. Therefore, of the clinical symptoms and signs requiring referral to the studied emergency services, CNS diseases were the most common, followed by respiratory diseases. The most important laboratory abnormal measurements were CRP, ESR, Hb, and liver enzymes. The study also showed that underlying diseases, such as cardiovascular and central nervous system diseases, were more effective than other underlying diseases.
Ranabothu et al. (
15) performed a pediatric study in 2020 and characterized the clinical features of children with confirmed COVID-19 infection based on available data. They report that the prevalence of COVID-19 in children is lower than in adults, with rates ranging from 1% to 5%.
Armin et al.’s (
16) study showed the mortality rate in Iranian children with COVID-19 in 2022 and that the mortality rate was 8.3% (59 from 711) in all age groups, more common in male children, especially in children with underlying diseases. Similarly, Efendi et al. (
17) conducted a study to predict the death rate of children with COVID-19 in Indonesia in 2023, which was reported as 2.7% lower than Armin et al.’s study (
16). In this regard, Flaxman et al. (
5) in 2023 found 1 person per 100,000 across all age groups, about 4 children under 1 year, 0.6 in children from 1 to 4 years, 0.4 for children from 5 to 9 years, 0.5 for children from 10 years to 14 years, and 1.8 per 100,000 for children aged 15 - 19 years. Efendi et al. (
17) reported that several factors, such as age, treatment, disease severity, and underlying medical conditions, had a significant effect on the mortality rate of children with COVID-19. In this way, it is possible that as age increases, the risk of dying from COVID-19 will decrease.
In 2020, a Brazilian study (
18) reported that the probability of in-hospital mortality was 4.8% during the first 10 days and increased with the length of hospital stay. In 2022, a study by Gonzalez-Dambrauskas et al. (
19) showed that deaths among children under 2 years of age with COVID-19 occurred more frequently in male children and about half of those with the diseases, such as lung and heart diseases.
To confirm the above-mentioned facts about the factors influencing mortality in children with COVID-19, Efendi et al. (
17) pointed to underlying diseases, such as heart disease, laboratory measurements, and clinical manifestations. In this regard, preventive measures and systematic management strategies are needed to improve outcomes in children with heart disease (
20) and the extent to which markers are monitored. Dynamic inflammation can help pediatricians assess and effectively evaluate the care of children and adolescents with multisystem inflammatory syndrome, especially as a priority during the COVID-19 pandemic (
21). The most common symptoms in children with COVID-19 are fever and cough, followed by diarrhea and abdominal pain, and very few children have severe clotting disorders, respiratory failure, shock, and kidney damage (
21).
Of the clinical presentations in the present study’s children with COVID-19, CNS diseases had a significant presentation, compared to others, when it has been reported that the clinical presentations were varied from GI symptoms, cardiac disease, mild or absent respiratory symptoms, variable incidence of rash, red eyes, and oral mucous membrane changes from center to center (
22). A study was performed in Iran by Kiani et al. (
23) in 2021 and reported fever (86.5%), asthenia (75.7%), and anorexia (73%) as manifestations of clinical symptoms. Moreover, abdominal pain (48.7%), diarrhea (45.9%), nausea and vomiting (37.8%), cough (32.4%), sore throat (29.7%), and shortness of breath (27%) were the most common symptoms.
Mantovani et al. (
24) in 2021 found that 47% of children with COVID-19 had a fever, 37% had a cough, 2% had a stuffy nose, and 1% had difficulty breathing. Children with mild symptoms accounted for 79% of cases; nevertheless, only 4% were in critical condition.
In 2020, two studies by Oualha et al. (
25) and Bixler et al. (
26) reported some facts about the relationship between underlying diseases and death due to COVID-19 such that Oualha et al. (
25) observed that 70% of their patients with COVID‐19 had underlying diseases, more frequently CNS (25.92%). Bixler et al. (
26) observed that among the 121 dead children due to COVID-19, 91 cases (75%) had underlying diseases. Of the children, 79 cases (65%) died after admission to a hospital, and 39 subjects (32%) died at home or in the emergency department (ED) (
26). Kiani et al. (
23) noticed that 12% of children had underlying medical conditions in which gastroenteritis was more common in their study. Ranabothu et al. (
15) concluded that the majority of children with COVID-19 had one or more underlying medical conditions, such as chronic lung disease and CVD.
In the present study of children, 42.6% (n = 78) had underlying diseases, such as hematology and CNS, that were more common, and those with heart disease had the highest mortality, followed by CNS diseases. Among 78 children with this underlying disease, 13.12%, 8.74%, 2.73%, 5.46%, 5.46%, 4.37%, and 2.73%, respectively, suffered from hematology, neurology, respiratory, endocrine, cardiovascular, renal, and digestive diseases. Consistent with the present study’s findings, Armin et al. (
16) observed that more than 90% of their children with COVID-19 had underlying diseases than in the present study. The aforementioned study demonstrated that 35.26% of the children with CNS had malignancy and primary immunodeficiency, and 8.82% had heart disease. A case series in Iran (
27) reported no underlying disease in children with COVID-19; however, Singh et al. (
28) detected neurological disease in 11.11% of patients with COVID-19. Kiani et al. (
23) reported that about 60% and 8% of children with COVID‐19 had Hb and mean corpuscular volume (MCV) less than normal levels, 80% and 60% had abnormal elevations in CRP and ESR, 32% and 35% had an increase in ALT and AST levels, respectively, and about 40% of them had hypoalbuminemia.
Armin et al. (
16) observed an increase in ESR, CRP, LDH, AST, and ALT and the presence of proteinuria and hematuria in more than 50% of patients. Qiu et al. (
29) noticed a decrease in lymphocyte counts, higher levels of procalcitonin and creatinine, and increased D-dimer levels in patients with COVID-19. Sun et al. (
30) reported normal or increased leukocyte count, high levels of CRP, procalcitonin, lactate dehydrogenase, and abnormal liver function. A study showed an association between admission to the pediatric intensive care unit (PICU) and higher levels of CRP, procalcitonin, and pro-B-type natriuretic peptide and platelet count (
31). Henry et al. (
32) observed that about 69.6% of the children with COVID-19 had normal leukocyte count and absence of lymphopenia due to milder disease. Furthermore, they revealed that an increase in procalcitonin levels could be caused by bacterial coinfection as a complication of COVID-19, also reported by Xia et al. (
33), with an increase in 80% of Chinese pediatric patients. Elevated liver enzymes that were reported in the present and the aforementioned studies might be related to the presented angiotensin-converting enzyme 2 (ACE2) in the intestines. Finally, and based on the available data, it is not possible to document a pattern of changes in the laboratory measures in pediatric COVID-19 based on disease severity.
Kiani et al. (
23) noticed that about a third of their children had breathing problems; nevertheless, chest X-rays were reported to be unspecific in most children. In this regard, the most common finding on chest CT scans was bilateral opacification, which has been reported by Hoang et al. (
34). These results are comparable to the results of the current study; among 147 individuals who underwent CT scans 3, 4, 2, 46.5, and 87 reticular, pleural effusion, atelectasis, opacified glass, solidification, and normal CT scans were present, respectively. Kiani et al. (
23) reported that their children with COVID-19 received antibiotics, such as ceftriaxone and clindamycin, and antiviral drugs, such as Kaletra. Alternatively, if needed, the patient is given a bronchodilator, such as Duolin or Ventolin, along with a nebulizer and oxygenated via a nasal cannula. In the present study, children 14, 37, 37, 9, 17, 3, 10, and 7 received intravenous immunoglobulin (IVIG) injections, prednisolone, remdesivir, favipiravir, hydroxychloroquine, lopinavir, Kaletra, and atazanavir, respectively. Moreover, in the emergency situation, antibiotics were used. Because the data were collected from the medical records of the patients, there were some constitutive limitations in the present study.
5.1. Conclusions
The present study concluded that the associated factors with death were laboratory measures, such as CRP, ESR, Hb, and liver enzymes, and underlying diseases, such as cardiovascular and central nervous system diseases. Knowledge regarding the clinical characteristics and disease burden in children with COVID-19 is the critical stage of the pandemic for better treatment, better control of transmission, and appropriate allocation of healthcare resources to decline mortality.