Immunity and COVID

The whole world is in turmoil because of the Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2). All strata of people have been affected, children less than 18 years of age accounting for 2%–5% cases globally. In 2019, children were less affected and suffered mild and asymptomatic cases. Some rare cases of complications such as multisystem inflammatory syndrome, severe cardiac symptoms have also been observed. Some of the risk factors for severe COVID 19 in children include obesity, chronic respiratory diseases (especially asthma), and a compromised or suppressed immune system.¹

It was observed that kids with obesity had a chronic pro-inflammatory status which along with the acute state of systemic inflammation, act as a risk factor for severe COVID-19 infection. It was also found that the cytokine storm found in severely COVID-19 infection adults were not found among obese children infected with COVID-19, but a dysregulation on their immune response, with increased titers of Interleukin-10 and low counts of neutrophil levels, were observed.² The clinicians have also reported cases of multisystem inflammatory syndrome in children (MIS-C), a severe inflammatory syndrome following coronavirus disease 2019 (COVID-19) exposure or infection.¹

In an Analysis of national-wide data from The Mexican Open Registry, pediatric cases of 21 161 patients younger than 18 years were collected. The Registry provided data regarding the age, sex, pre-existing conditions, whether the patient is infected with SARS-CoV-2, its clinical progression to COVID-19 pneumonia, the need for regular or Intensive Care Unit Admission or death. The three commonly pre-existing conditions were immunodeficiencies (3.8%), asthma (3.8%) and obesity (3.1%). The study also concluded that obesity increased the chances of SARS-CoV-2 infections by about 39% and immunodeficiencies by 23%. Immunodeficiencies were subsequently associated with 4-fold rates of COVID-19 pneumonia and an 8-fold probability of admission with SARS-CoV-2/MIS-C. It was also observed that children and adolescents with hypertension had a 7-fold probability and patients with chronic kidney disease had a 5 fold probability of being admitted after being tested positive with SARS-CoV-2 positive. Other children at a risk were patients with cardiovascular diseases (1.7%), asthma, and type 1 diabetes (0.6%).³

A cross-sectional survey of 584 households in the United States reported that obesity due to weight gain during lockdown was a concern. The use of highly processed foods, increase in consumption of snack foods and desserts resulted in weight gain among elders, adolescents and children. A study in Italy among 41 obese youth showed that the intake of potato chips, red meat, and sugary drinks had increased significantly while outdoor activities and sports decreased during the first 3 weeks of the national lockdown leading to the obesity epidemic, which in turn increased the risk among the obese children being infected by COVID-19 infection.¹ 

Chronic respiratory disease, asthma and other respiratory conditions were thought to increase the risk among children in developing COVID-19 infection. But some studies among ICU patients did not show a significantly higher proportion of asthmatics. The study also reported that underlying respiratory conditions were present in only 4.3% of those requiring general care, while 10.4% among those requiring ICU care. In another study among COVID-19 pediatric cases in Mexico, asthma was reported in 3.8% (806) of all cases, but was not associated with increased severity of infection; those reporting asthma were not more likely to develop pneumonia, nor were they at higher risk for hospitalization.³

The risk of getting infected by COVID-19, due to immune system compromise is not confirmed. In a study in South Korea, no immunodeficiency was reported among 91 pediatric cases accounting for 76.5% of all pediatric cases in the country, excluding a cluster outbreak within a religious community. In Spain, 15% of the total pediatric COVID-19 cases were immune-compromised for 1 month. 8.1% of pediatric cases in the UK used immunosuppressants before being hospitalized for COVID-19. In Mexico, 3.8% of cases were suffering from immunodeficiency and cases were associated with a four-fold increase of COVID-19 pneumonia and an eight-fold increase in the risk of hospital admission. Data regarding the presence of viral co-infections within the COVID-19-positive pediatric population is limited. ³

Studies have shown that indoor air pollution (IAP) and pre-existing morbidities act as a risk factor for Coronavirus disease among children under five. Indoor air pollution may include indoor biomass combustion, the air pollutants which are emitted include suspended particulate matter (SPM), nitrogen oxides (NOx), carbon monoxide (CO), benzene (C6H6), 1, 3-butadiene (C4H6), methanol (CH2O), polycyclic aromatic hydrocarbons (PAHs), cooking fuels mostly used in rural home-like coal, lignite, charcoal, wood, straw/shrubs/grass, agricultural crop, animal dung, etc. Additionally, smoking of cigarettes, bidis, and pipes among children and adolescents also act as risk factors.⁴

Thus the studies show that obesity, respiratory disease, immunodeficiency, air pollution contributed to increase in risk of being infected by COVID-19. Hence, control on junk food intake, boosting immunity, having nutritious and balanced diet, reducing pollution and constantly guiding the children to follow the preventive measures can help to reduce the risk factors, protect children and prepare for any future epidemics.

REFERENCES:

1. Melissa K. Siebach RN B, Giovanni Piedimonte, Sylvia H. Ley COVID-19 in childhood: Transmission, clinical presentation, complications and risk factors. Pediatric Pulmonology. 2021;Volume56, Issue6:1342-56.
2. Huan Wu  HZ. Clinical and Immune Features of Hospitalized Pediatric Patients With Coronavirus Disease 2019 (COVID-19) in Wuhan, China. JAMA Netw Open. 2020;3(6):e2010895. .
3. Leon-Abarca JA. Obesity and immunodeficiencies are the main pre-existing conditions associated with mild to moderate COVID-19 in children. Pediatr Obes. 2020;15(12):e12713. .
4. Chouhan JSaP. Indoor air pollution (IAP) and pre-existing morbidities among under-5 children in India: are risk factors of coronavirus disease (COVID-19)?. Environ Pollut 2020; 266 , 115250:1-8.