PARTICULARITIES OF RESPIRATORY MANIFESTATIONS OF COVID-19 INFECTION OF CHILDREN

the the significance of in Results. As a result of 21 cases, this study discovered a higher frequency of the disease in infants. The nosological expression of the infection was dominated by pneumonia and unique cases of infection in four children with upper respiratory infections. Eleven children showed severe evolution, the moderate form being the dominant one. An almost constant feature in children in the study was a febrile syndrome, which in 31 cases was > 38.0 o C. Every second child showed catarrhal respiratory signs, cough, and cyanosis in 66.1% of the children, chest circulation in 32.1% of the cases, wheezing in 6 children. COVID-19 infection in hospitalized children in respiratory complications in 81.3% of cases


INTRODUCTION
A sudden outbreak of a new type of pneumonia caused by coronavirus in Wuhan, China, at the end of 2019, wreaked havoc on both Chinese society and the global community. The SARS-CoV-2 infection has devastated social and economic life worldwide, thus reorienting the population's goals and priorities. Initially, specialized literature claimed that children and teens are less prone to complications and severe forms of infection. However, even if they have poor clinical manifestations, this group of people plays an important role in spreading the infection (1).
Epidemiological data from the early stages of the pandemic suggest that children present a much milder course of the disease than adults do. A mild clinical presentation or asymptomatic nature of the pediatric infection with SARS-CoV-2 might generate false data, especially when limited testing capabilities mask a tendency toward more severe cases of the disease in the population (2). However, imaging and laboratory data of post-COVID children demonstrate a different reality, even if the clinical manifestations are less pronounced. A predominance of uneven infiltrations, consolidations, and, to a lesser extent, groundglass opacities are reported from patients' chest imaging examinations (3).
The pandemic has serious and multifaceted consequences for young children, including impaired mental health, delayed or stopped progress in schooling, complications due to delayed necessary medical care, malnutrition, poverty, and domestic violence (2).
In comparison with the other viruses, SARS-CoV-2 viral ribonucleic acid (RNA) is subject to replication errors and mutations, reducing its virulence. Therefore, children could be infected more frequently with a virus of the second or third generation, leading to milder cases. Recent evidence suggests that the cellular receptor for the angiotensin 2 converting enzyme (ACE2) and transmembrane protease-serine 2 (TMPRSS2), which are needed for SARS-CoV-2 to enter cells and be distributed in various organic tissues, may be different in children and adults. In children, ACE2 receptors may have a different structure, concentration, or ability to connect to the virus (4).
Children with COVID-19 present a variety of symptoms. The most common are fever, fatigue, headache, catarrhal respiratory signs with nasal congestion, serous rhinorrhea at onset, dry cough and then with sputum, gastrointestinal symptoms like diarrhea, and general symptoms (5,6,7). Although most children and young people suffer from mild or asymptomatic forms of the disease, severe cases and associated complications have recently been reported. A wide range of signs and symptoms found in children vary from fever and systemic inflammation to myocardial damage, resulting in tissue injury and shock in some patients, to the development of coronary artery dilatation/aneurysms.
Aim of the study. The objective of this study was to describe the characteristics of clinical signs of respiratory system in children hospitalized with COVID-19 infection in the Institute of Mother and Child.
Hypothesis of the study. It is suggested that children do not appear to be at higher risk of severe illness, but it needs more studies on the role of comorbidities in the severity of pediatric COVID-19 infection.

Data collection
A retrospective descriptive study with medical charts was performed during the period March-July 2021, that included 64 children from the COVID-19 department of the Institute of Mother and Child, with a mean age of 2.04±0.4 (variations from one day to 17 years). The study methodology expected the assessment of the following information: the onset of the disease, general symptoms (febrile syndrome, fatigue, headache), catarrhal respiratory signs (nasal congestion, serous rhinorrhea at onset, cough), and complications developed during the disease within the COVID-19 infection episode.

Eligibility Criteria
All children who were confirmed SARS CoV-2 positive by molecular biology tests and/or rapid tests for the detection of SARS-CoV-2 antigen.

Data processing
All collected data were introduced into the Excel program, and the statistical data was calculated using the Epi Info program, based on different criteria.
Confirmation of the clinical diagnosis was made according to the National Clinical Protocol "Coronavirus infection of new type (COVID-19)" criteria in the new type of coronavirus infection and was based on positive molecular biology tests and/or rapid tests for the detection of SARS-CoV-2 antigen (7,8,9,10).
Children have a smaller variety of activities. Therefore, they are primarily infected in their family community, which is also confirmed in our study, where 34 children (53.1%: 95%CI 40.2-65.7) were confirmed after their parents had been tested and the results proved to be positive.
Amongst confirmed cases through laboratory tests, 12.9% were asymptomatic, 43.1% had mild symptoms, 40.9% had moderate symptoms, and 2.9% had severe symptoms or critical illness. The proportion of severe or critical cases was higher in children under 1 year of age (3,6,7,10,11). In children included in the study, the course of SARS-CoV-2 infection is acute and evolves with moderate severity manifestations in 58±0.7% of cases. The study looked at hospitalized children who had a progressive illness that increased to a severe illness and required specialized treatment. For them, clinical symptoms developed with marked fever, general symptoms with toxi-infectious syndrome that were recorded most frequently in newborns (58.3%: 95%CI 27.7-84.  Febrile syndrome was recorded in 48.4%: 95%CI 35.8-61.3, χ 2 =3.18, p>0.5, but subfebrility in 51.6%: 95%CI 38.7-64.3 cases of children with COVID-19 infection. Febrile syndrome is recorded as the only symptom in more than 30% of patients (3,7), and it is more common in hospitalized children (71.8%) than in those who received treatment at home (27.4%).
Signs of respiratory distress were predictable given the severity of respiratory failure. Dyspnea was perceived in 14.1%: 95%CI 6.4-26.2 cases, and chest circulation in every third child, 32.8%: 95%CI 20.3-45.9. The severe form of the disease has been noted most frequently in younger children, from birth to 7 years old. The most common clinical symptom by stetoacustic evaluation is coarse breathing (97%: 95%CI 87.7-99.6). Pathological respiratory sounds are not characteristic respiratory manifestations in the COVID-19 infection. The wheezing dry rales are heard in every fourth child from the study, crackling rales in 14%: 95%CI 6.4-26.2 cases; less often, moist rales that have been found in 5.4%: 95%CI 1.12-14.9 cases. A total of 4% of the children with SARS-CoV-2 infection had oxygen saturation values (measured by pulsoxymetry) of 95.6±0.3% with a minimum of 90% and a maximum of 98%. Among them, 11 children (22%: 95%CI 11.5-36 cases) needed respiratory support from the mask and nasal cannulas. Compared to the age of the children, the lowest SpO2 was appreciated in antepreschool children (94.8±0.5%), the others having SpO2 higher than 95%, F stat = 2.9, p<0.04. The most common clinical symptom by stetoacustic evaluation is coarse breathing (97%: 95%CI 87.7-99.6). Pathological respiratory sounds are not characteristic respiratory manifestations in the COVID-19 infection. The wheezing dry rales are heard in every fourth child from the study, crackling rales in 14%: 95%CI 6.4-26.2 cases; less often, moist rales that have been found in 5.4%: 95%CI 1.12-14.9 cases. A total of 4% of the children with SARS-CoV-2 infection had oxygen saturation values (measured by pulsoxymetry) of 95.6±0.3% with a minimum of 90% and a maximum of 98%. Among them, 11 children (22%: 95%CI 11.5-36 cases) needed respiratory support from the mask and nasal cannulas. Compared to the age of the children, the lowest SpO2 was appreciated in antepreschool children (94.8±0.5%), the others having SpO2 higher than 95%, F stat = 2.9, p<0.04.

DISCUSSIONS
The impact of COVID-19 on the pediatric population is incompletely understood (1). Children infected with SARS-CoV-2 (3,(9)(10)(11) are less likely to develop symptomatic or serious diseases. Among symptomatic children, the most common clinical features were fever and respiratory symptoms, followed by gastrointestinal manifestations.
In our study, we described the characteristics of the evolution of COVID-19 infection in children, with an evaluation of the evolutionary peculiarities in different age groups. Analyzing the age structure shows that infants were the most likely to get sick. Although some instances were asymptomatic, the majority had mild to severe symptoms, which needed specialized care. Respiratory syndrome manifested itself mainly with both subjective and objective signs along with the change in the auscultatory picture.
The rate of premature delivery has increased, and SARS-CoV-2 infection is proportionately higher in premature neonates, which appears to be related to premature delivery (3,10,11). In our study, children up to one month of age developed more severe forms with complications. Disease might affect newborns who acquired the infection from their mothers, suggesting a possible perinatalperipartum transmission. Our analysis showed that pediatric patients acquired infections mainly through close contact with their parents or other family members.
Among the patients included in the study were children with comorbidities such as cystic fibrosis (1 patient), carious malformations (2 patients), neurological disorders (1 patient), coagulation abnormalities (3 patients), allergic conditions (2 patients), prematurity (2 patients), and a case of death on the background of COVID-19 due to comorbidities (multiple birth defects).