The probability of developing an infection from touching surfaces in public buildings—even healthcare facilities—is about 80%, according to Charles Gerba, PhD, a microbiologist at the University of Arizona in Tucson.

“Every time you touch one of these surfaces, you are picking up 30% to 40% of the organisms on that surface,” Gerba explained, adding that adults then touch their faces about once every three to four minutes, and children do so more frequently, which is how they would become infected from a virulent virus.

“We learned that the hand is quicker than the sneeze in the spread of disease,” Gerba said.