BMJ Sub-Journal: Children's special immune systems and blood vessels reduce their risk of developing COVID-19

December 4, 2020 /--- -- Differences with the adult immune system and better vascular health levels are 10 factors in protecting children from severe COVID-19, according to a new review.
the findings were reviewed by experts from the Murdoch Institute for Children's Science (MCRI), the University of Melbourne and the University of Fribourg and published in Archives of Disease in Childhood to clarify the severity and symptoms of COVID-19, the cause of the age difference.
(Photo: www.pixabay.com) MCRI and University of Melbourne professor Nigel Curtis say that while many hypotheses try to explain why adults are at higher risk and that children are protected from serious illnesses and deaths from COVID-19, most do not explain why the sharp rise in COVID-19 severity occurs mainly among older people aged 60-70.
Curtis said that in contrast to other respiratory viruses, there are relatively few serious diseases and deaths caused by COVID-19 in children.
"Most children with COVID-19 have no or only mild symptoms, the most common being fever, cough, sore throat, and changes in smell or taste."
even children with the usual risk factors for serious infection, such as low levels of immunity, do not have a high risk of severe COVID-19 disease.
" Professor Curtis said that as we get older, damage to endothor cells in various organs, especially blood vessels, heart and lymphatic tubes, increases, and there is a link between the conditions that affect these cells and severe COVID-19.
"We know that pre-existing vascular damage plays an important role in the severity of COVID-19 and can lead to blood clots, strokes and heart attacks."
COVID-19 can infect these endosthel cells and cause inflammation of blood vessels.
children's endoeskins suffer much less damage than those of adults, and their clotting systems vary, making children less prone to abnormal blood clotting.
" chronic inflammation-related diseases develop with age, including diabetes and obesity, which are also associated with severe COVID-19.
addition, recent immunizations using live vaccines, such as the MMR vaccine against measles, mumps and rubella, may strengthen the immune system and may play a role in protecting children.
, from the University of Fribourg, says there are other important differences in the immune systems of children and adults.
children have a stronger inno-immune response, which is a first-line defense against COVID-19," she said.
important factor is 'trained immunity', which stimulates innate immune cells after mild infection and vaccination, leading to a 'congenital immune memory'.
infected with COVID-19 are often infected with the same virus as other viruses.
infection with the virus can improve trained immunity and enable children to remove COVID-19 more effectively.
" in addition, different levels of the microbiome (bacteria and other bacteria) in the throat, noise, lungs and stomach also affect sensitivity to COVID-19.
" microbiome plays an important role in regulating immunity, inflammation and disease prevention.
children are more susceptible to viruses and bacteria, especially the nose, which may limit the growth of COVID-19.
" vitamin D levels and their anti-inflammatory properties are also generally higher in children.
" correlation between severe COVID-19 risk factors and vitamin D deficiency, including obesity, chronic kidney disease, and black or Asian ancestry, suggests that vitamin D supplementation may play a role in helping to prevent or treat COVID-19.
Curtis said understanding the potential differences in age-related COVID-19 severity would provide important insights and opportunities for the prevention and treatment of SARS-CoV-2 infections.
(Bioon.com) Source: Differences in immunity and blood vessels likely protect children from severe COVID-19 Original source: Petra Zimmermann et al, Why is COVID-19 less severe in children? A review of the proposed mechanisms underlying the age-related difference in severity of SARS-CoV-2 infections, Archives of Disease in Childhood (2020). DOI: 10.1136/archdischild-2020-320338。