In an article published on March 10 in the Conversation, Bridle explained that regular exposure to the environment is critical for children's immune systems to learn to differentiate between safe versus disease-causing germs.
A concept in immunology called "hygiene hypothesis" states that interactions with the microbial world – an environment full of bacteria, parasites, viruses and other microorganisms – after birth are extremely important for the proper development of the immune system.
"The immune system is a learning device, and at birth it resembles a computer with hardware and software but few data. Additional data must be supplied during the first years of life, through contact with microorganisms from other humans and the natural environment," according to a 2016 study cited by Bridle.
Billions of germs reside inside and outside a healthy person's body. Under normal circumstances, they have a mutually beneficial relationship with their host and promote a robust immune system. But inadequate exposure to the microbial world can weaken young children's immunity against diseases.
Bridle used the study's computer analogy to explain why. According to him, the "data" that gets uploaded into the "software" are incomplete, which can cause the immune system to struggle distinguishing between "bad" and "good" bacteria. This, in turn, can lead to allergies, asthma and autoimmune diseases.
Unfortunately, modern-day societies tend to adopt behaviors that limit exposure to germs, such as the overuse of antibiotics and even urbanization, which Bridle said is similar to living in a "concrete jungle." In fact, studies show that urbanization is partly to blame for the rise of exercise-induced asthma in many middle-income countries over the past several decades. (Related: Prevent asthma by cleaning less: Increased exposure to allergens and pet dander actually reduces risk.)
However, this doesn't mean that proper hygiene is not necessary. Bridle clarified that proper hygiene is important especially in the context of infection prevention. In fact, he noted, advocates of the hygiene hypothesis discourage the use of the term because it can be misinterpreted to mean that hygiene harms a developing immune system.
For Bridle, the best way to approach hygiene is to practice moderation and "targeted hygiene," which focuses on implementing sanitary measures at crucial points, such as when handling food, eating, using the bathroom, caring for pets, disposing of garbage and handling dirty laundry.
Bridle is concerned that pandemic restrictions negatively impact children's immune system. He noted that government-led responses, such as lockdowns and mask mandates, severely limited children's interactions with the outside world, thereby increasing their risk of an underdeveloped immune system.
"Most of their extracurricular activities have been cancelled and they have been discouraged from leaving their homes. Even the air they breathe is often filtered by masks and there is prevalent use of hand sanitizer," Bridle wrote. (Related: Lockdowns, masks destroying mental health of children and young people.)
The very young are the most vulnerable, he said, because more immature immune systems are more prone to becoming dysfunctional. As such, the problem will likely be more prevalent among infants and toddlers, but older children can also suffer from a weakened immunity. Bridle explained that while the immune system is largely mature by around age six, some essential components are still developing as children enters adolescence.
"An unfortunate and under-appreciated long-term legacy of this pandemic will likely be a cluster of 'pandemic youth' that grow up to suffer higher-than-average rates of allergies, asthma and autoimmune diseases," Bridle said.
He added that pandemic restrictions can also cause children to develop hypersensitivities to mRNA vaccines, such as the Pfizer-BioNTech and Moderna vaccines, when they get older. mRNA vaccines are known to trigger severe allergic reactions in people with a history of allergies.
Bridle ended his article with a warning: Children raised in largely isolated and highly sanitized environments are at greater risk of developing allergies and autoimmune diseases than anyone before them.
"The immune systems of children are not designed to develop in isolation from the microbial world, so let’s consider letting children be children again," Bridle concluded.
Learn more about the impact of pandemic restrictions on health at Pandemic.news.