You’re right to be worried, because sleep deprivation does take a toll on the immune system. Getting adequate rest is important all the time, but it’s especially crucial during cold and flu season.
You may be surprised at just how much sleep your little ones need per night, because it’s often much more than adults typically get. The American Academy of Pediatrics makes the following recommendations for sleep requirements by age:
Here's more information about sleep apnea, sleep and insomnia: