What Goes Around, Comes Around

Step 1: Curtis brings a minor cold home from school. Runny nose, some coughing. Duration: 1 week.
Step 2: Jenny develops sore throat and runny nose with fatigue. Duration: 2-3 days.
Step 3: Thomas starts sneezing with congested breathing, general grumpiness, and occasional snot dripping from nose (total gross-out). Duration: 2 days and counting.
Step 4: Today, Curtis has a sore throat and runny nose.

Lather, rinse, and repeat.