Infants have unexplained immunity to coronavirus

Baby: Petr Kratochvil (via Creative Commons)

By Milli Jayadeep

Coronaviruses belong to a virus family specific to the Middle East but it has been circulating global news recently due to the contagious nature and the symptoms and fatalities caused by it. Patients experience respiratory symptoms, fever and cough. In more severe cases, it can develop into pneumonia and severe acute respiratory syndrome. 

With the new coronavirus outbreak it has been noted by the scientific community that, children are a group of individuals seeming to be less affected. There are only 9 reported cases of infants who have been taken to hospital following the infection. The age group ranges from 1-11 months and showed milder symptoms than affected adults. None of the infected children showed any of the expected severe symptoms. 

There has been a lot of speculation about why fewer children were affected compared to adults. It has been suggested that babies may be less likely to become infected or are at a lower risk of exposure to the virus. 

Also there is higher activity in the innate immune response in a child than that of an adult, which may well explain this unusual phenomenon. Innate immunity is a non-specific immune response against pathogens, this is a defence mechanism passed to the child through vaginal delivery and breastfeeding. The immune system of a child is considerably more resilient than that of adults. Children also have faster recovery systems when exposed to pathogens, so are more likely to respond better to infections. A published statistic states that adults are 25 times more likely to die from a chickenpox infection than children, demonstrating the efficiency of the younger immune system of children.

Another explanation could be that they have better respiratory health, as a result of  less exposure to cigarette smoke and air pollution when comparing the respiratory system in adults. It was also observed that children have less chronic problems and have better health in general. Many chronic conditions develop over time so it is possible that children have simply not had the time to develop these conditions.

Adults are also more likely to develop immunological complications such as acute respiratory distress syndrome (ARDS) seen in the more severe cases of coronavirus infection. ADRS is where the immune function fails and consequently leads to inflammation and fluid build-up. On the other hand, children had pneumonia, which is a development of the coronavirus infection. However, this did not escalate to cause further immunological complications. 

In conclusion, there are a variety of explanations as to why infants are less likely to develop coronavirus but as highlighted above they are poorly understood by the scientific community to date. It does however provide some hope that infants are less vulnerable and should not become infected.