Excessive use of hand sanitizers: while hand sanitizer and other soaps can be necessary, their excessive use can lead to decreased exposure to microbes because they tend to kill a wide range of bacteria.
Excessive use of antibacterial cleaning supplies: in peoples’ homes, the use of cleaning supplies can kill many bacteria, creating nearly sterile environments. This causes a decreased exposure to microorganisms.
Less time spent playing outside: people, especially children are exposed to a plethora of microbes when playing outside, and over the course of the past few decades with the introduction of video games and the internet, children have spent less time playing outside.
Increased antibiotic use: antibiotics often kill a wide range of microbes, many of which are beneficial symbionts of humans. By taking antibiotics unnecessarily or for prolonged periods of time, a person is selecting for microbes with the capacities to evade these antibiotics.
