A Patient States That Her Family Has Had Several Colds

A patient states that her family has had several colds during this winter and spring despite their commitment to handwashing. The high communicability of the common cold is attributable to what factor?

A) Cold viruses are increasingly resistant to common antibiotics.
B) The virus is shed for 2 days prior to the emergence of symptoms.
C) A genetic predisposition to viral rhinitis has recently been identified.
D) Overuse of OTC cold remedies creates a rebound susceptibility to future colds.