Why Infants are Less Affected by COVID-19 Than Adults?

Infant immune system is stronger than people think and beats the adult immune system at fighting off new pathogens, shows a new study published in the journal Science Immunology.

The infant immune system has a reputation for being weak and underdeveloped when compared to an adult, but the comparison isn't quite fair, says Donna Farber, Ph.D., professor of microbiology & immunology.

‘Understanding the distinct immune responses in infants could help in designing more effective COVID-19 vaccines for children.’

In the new study, researchers tested only the immune system's ability to respond to a new pathogen, essentially eliminating any contribution from immunological memories.

For the head-to-head comparison, they collected immune cells that have never encountered a pathogen from both infant and adult mice. The cells were then placed into an adult mouse infected with a virus.

The T cells from infant mice detected lower levels of the virus than adult cells and the infant cells proliferated faster and traveled in greater numbers to the site of infection, building a strong defense against the COVID-19 virus.

A laboratory comparison found similar enhancements among human infants compared to adult T cells. This shows that infant immune system is much better than the adult since it's designed to respond to a multitude of new pathogens.

That appears to be playing out in the case of COVID-19, which is new to absolutely everybody. Adults faced with a novel pathogen are slower to react. That gives the virus a chance to replicate more, and cause more complications.

The findings also help explain why vaccines are particularly effective in childhood when T cells are very robust and this could also lead to better vaccine designs.



Source: Medindia