This study aimed to investigate the prevalence of COVID-19 in children who were admitted with acute respiratory symptoms in Kerman Province hospitals, southeastern Iran, during the 2020 epidemic. In this regard, 97 children were hospitalized with acute respiratory syndrome from February 20 to May 14, 2020. Out of them, thirteen patients were diagnosed as COVID-19 according to the criteria of the World Health Organization. During the same period, 817 adults were admitted to the hospitals in this area who were diagnosed to be infected by COVID-19. Severe involvement and hospitalization have also been lesser in children in other studies compared to adults (
13). In a large study performed in China, only 2.1 percent of the patients were under 19 years old (
14). Findings from other studies also showed that children are less involved than adults and usually recover within 7 days (
15).
There are several reasons why children are less likely to have severe illness compared to adults. Explaining, children’s T cells’ immune system works differently against childhood pathogenic viruses, which has a cross-immunity with different viruses. Besides, various vaccinations that are given in childhood increase the strength of immunity. The immune system of children is evolving and still has not become as active as adults for self-attacking. Moreover, virus receptors, like ACE, are different in children and adults (
16).
On the other hand, a low incidence of the disease in children could be due to mild symptoms and lack of attention and identification of the patients. Also, false-negative diagnostic molecular tests in children, closure of kindergartens, and schools during an epidemic are known as the other causes of the low incidence of the disease in children (
15).
Out of 97 patients who were hospitalized due to acute respiratory syndrome, 26 (27%) had an underlying disease. Correspondingly, there was no significant difference between the two groups in this regard. The epidemic of COVID-19 in the region began at the end of the acute respiratory illnesses season, resulting in a decrease in the acute respiratory viral illness and a lower number of hospitalized patients. Because of the fear of infecting by a coronavirus, many patients with mild respiratory problems, who had no underlying disease, preferred to not be admitted to a hospital.
The history of antibiotic usage before hospitalization was significantly lower in children who were ultimately diagnosed with COVID-19 compared to the other patients. In this regard, it could be potentially due to the low incidence of bacterial infections such as otitis media and sinusitis following COVID-19 (
17). Another cause of the lower rate of antibiotic use in children with COVID-19 may be due to a more rapid progression of respiratory diseases than the non-COVID-19 group.
Fever and cough were known as the most common clinical symptoms. Fever was significantly higher in patients with COVID-19 than in non-COVID-19 patients, and this finding is consistent with other studies (
14). Also, other symptoms, such as gastrointestinal symptoms, were not different between the COVID-19 and non-COVID-19 patients. No study compared the COVID-19 and non-COVID-19 patients concerning their gastrointestinal symptoms, but in some reports, children showed more gastrointestinal symptoms than adults (
4).
There was no significant difference between the COVID-19 and non-COVID-19 patients in terms of laboratory findings such as WBC, leukopenia, lymphopenia, thrombocytopenia, LDH level, and CPK level. The rate of leukopenia was observed more frequently in the COVID-19 patients than non-COVID-19 ones. Although this difference was not statistically significant, it might be due to the low number of patients in the COVID-19 group. The same pattern was observed in regard to lymphopenia in our patients. Notably, in a study, lymphopenia had been relatively common, and a high CRP level has been cited as a marker of the disease severity in adult patients with COVID-19 (
18,
19).
In this study, the most common findings in chest CT scans of the patients with COVID-19 were bilateral patchy infiltration, and only one patient had a view of the ground glass opacity. In a similar study performed in the north of Iran, grand glass appearance has been reported in 25% of patients (
8). Other studies in other countries have also shown ground glass involvement in a small percentage of children with COVID-19 (
20).
Four (31%) patients with COVID-19 and 23 cases (27%) out of non-COVID-19 patients needed special care in the intensive care unit. There was no significant difference between the two groups in terms of intensive care, antibiotic usage, and the need for oxygen, which is consistent with the results of similar studies (
18). Also, four patients (31%) diagnosed with COVID-19 had received chloroquine as an antiviral drug. Also, in other similar studies, a small percentage of the patients received antiviral drugs (
21).
In this study, the overall mortality rate was 8%. However, this mortality rate appears to be high, but due to the epidemic of COVID-19 and the fear of hospitalization, most of the patients were ill with an underlying disease. Out of 13 COVID-19 patients, there were two deaths. An 8-month infant had a developmental disorder and seizure, and also, another one had chronic lung disease. Although mortality is low in children with the disease, it can occur in patients with underlying diseases (
22). The most important limitation of this study was the low number of the included patients. For a more detailed comparison, a larger study should be proposed at the national level.
5.1. Conclusions
Compared to the adults, the incidence of COVID-19 is lower in children hospitalized with acute respiratory syndrome. Severe complications of the disease and mortality occur in those children with underlying diseases. Most of the children with COVID-19 recover with supportive care with no need for specific treatment.