Why novel coronavirus does not affect children the same way as it affects adults

Children of all age groups are susceptible to COVID-19. Though, they present with symptoms of mild to moderate infection, which can easily go unnoticed.

Myupchar March 18, 2020 16:34:54 IST
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Why novel coronavirus does not affect children the same way as it affects adults

By now, the general assumption was that the novel coronavirus affects the elderly, sick and immunocompromised people the most. Children were seemingly less affected by the disease. This is unlike the cold and flu that affect children most severely. 

However, a research team in China said that children of all age groups are susceptible to COVID-19 . Though, they present with symptoms of mild to moderate infection, which can easily go unnoticed. If this is true, children may be a major contributor to the spread of the disease.

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Representational image. Image source: Getty Images.

The research is already peer-reviewed and is set to be published soon in the journal Pediatrics released by the American Academy of Pediatrics.

Variations in symptoms

For the study, Yuanyuan Dong and her team at the Shanghai Jiao Tong University, China, studied 2,143 pediatric patients of COVID-19 in China. The children had a median age of 7 years with age varying from 1 day to 18 years.

The symptoms were divided into different categories: 

  • Asymptomatic: Absence of any symptoms.
  • Mild: Fever, muscle ache, fatigue, runny nose, sore throat, and sneezing. Or an absence of fever with a stomach ache, diarrhoea, nausea and vomiting. 
  • Moderate: Fever, pneumonia, cough (could be dry or wet), with or without wheezing and usually no shortness of breath. Some moderate cases may not have any symptoms but lung lesions do show up on taking lung CT scans.
  • Severe: Cough, fever, and diarrhoea that progress to shortness of breath and bluish discolouration of lips and tongue within a week. 
  • Critical: Initial symptoms quickly progress to respiratory failure and shock, brain and heart damage, heart failure, blood clotting issues and acute kidney damage.

All of these symptoms are general and not limited to children. 

Here is what the team found out:

  • All children were susceptible to COVID-19 though infants were more vulnerable to the infection.
  • Children get a less severe infection than adults. Of all the cases of infection in children, only 5.9% were severe and critical. On the other hand, 18.5% of cases in adults were found to be severe and critical in the same timespan.
  • Both the genders were equally affected though the number of boys was slightly higher in the study than girls.
  • Among children, the frequency of severe and critical cases decreased with increasing age. About 10.6% of children who were less than one year of age got a severe and critical illness. This occurred in only 3% of children who were above 15 years of age.

However, most of the severe and critical cases were found in the suspected group rather than the confirmed group. So, there is a chance that these cases were something other than COVID-19 .

Possible causes

Dong and team attributed several possible causes to this difference in trend. The most obvious one was that children are less at risk of being exposed to infected people since they are at home most of the time and are well cared for. 

They also listed the following possibilities:

Children don’t have enough receptors for COVID-19 : It is believed that the novel coronavirus (SARS-COV-2) binds to the same receptor as the SARS virus - Angiotensin-converting enzyme II (ACE2). 

ACE2 is a receptor for an enzyme of the same name and is present on the surface of the heart, lungs and intestines. ACE2 plays an important role in maintaining blood pressure and electrolyte balance. However, SARS virus (and possibly the novel coronavirus too) uses it to enter into healthy cells.

It is possible that the ACE2 receptors in children are not yet fully mature, because of which the virus can't bind as well with these receptors. This leads to the children not getting a severe form of the COVID-19 .

Presence of antibodies: Children are susceptible to and get viral respiratory infections more often, especially in winters. Chances are they already have a huge number of antibodies against viruses in their blood - more than most adults do. 

Growing immune system: Children don’t have the same immune system as adults. Their immune system is still developing and hence, it may react differently to a new pathogen than adults.

For more tips, read our article on Coronavirus.

Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.

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