Babies Have Stronger Immune Systems, U.S. Study Reveals
Babies may get a lot of diseases, but that’s mostly because they’re only encountering infections for the first time, says Donna Farber, professor of microbiology & immunology at Columbia University Vagelos College of Physicians and Surgeons. Infants are faced with these pathogens for the first time and they do a pretty good job of handling them, Mihai Andrei reported for ZME Science.
Photo Insert: In some aspects, babies are stronger than adults.
"Adults don’t get sick as often because we’ve recorded memories of these viruses that protect us,” Farber says, “whereas everything the baby encounters is new to them.” In a new study, Farber and colleagues wanted to see the immune system of infants and adults go toe-to-toe without the previous experience of adult immune systems.
To level the playing field, they only tested the immune system’s ability to respond to a new pathogen. Infants have less developed immune systems than adults but can still respond to a plethora of infections and in some cases better than adults, the researchers write.
To conduct a relevant comparison, they collected naïve T cells (cells that have never encountered a pathogen before) from both adult and infant mice, as well as adult and infant humans. The cells were then placed into an adult mouse that had been infected with a virus.
When it came to eradicating the virus, the T cells from infant mice won handily, proliferating faster and traveling in greater numbers to the site of infection, mounting a strong defense against the virus. The researchers found the same thing when they looked at human cells.
“We were looking at naïve T cells that have never been activated, so it was a surprise that they behaved differently based on age,” Farber says. “What this is saying is that the infant’s immune system is robust, it’s efficient, and it can get rid of pathogens in early life. In some ways, it may be even better than the adult immune system, since it’s designed to respond to a multitude of new pathogens.”
“SARS-CoV-2 is new to absolutely everybody, so we’re now seeing a natural, side-by-side comparison of the adult and infant immune system,” Farber says. “And the kids are doing much better. Adults faced with a novel pathogen are slower to react. That gives the virus a chance to replicate more, and that’s when you get sick.”
The finding could also explain why many vaccines seem to be more effective when administered in childhood — because the T cells are more robust. Studies such as this one could not only help develop better vaccines for children but also help doctors pinpoint what the ideal period for vaccination is.
According to Farber, that period is during childhood, and doctors shouldn’t be afraid to recommend multiple vaccines during that time window. The study was published in Science Immunology.