The school week is spent in an enclosed space with hundreds of other children ( many of whom do not have sophisticated hygiene practices ) , which can provide stress to any student 's immune system . Asthma hospitalizations peak 17 days after Labor Day , studies show . Outdoor and indoor allergens can work together to create ` ` perfect storm '' for asthma . Contagious viral infections can also play a role when students go back to school .
Asthma hospitalizations peak 17 days after Labor Day , studies show . Outdoor and indoor allergens can work together to create ` ` perfect storm '' for asthma . Contagious viral infections can also play a role when students go back to school .