The students observed that about three of every four people tried to cover their cough or sneeze, in at least a token attempt to prevent germs from flying through the air. But the students discovered that most people, about two of three, used their hands to do it.
"When you cough into your hands, you cover your hand in virus," said study author Nick Wilson, an associate professor of public health at the Otago University campus in Wellington. "Then you touch doorknobs, furniture and other things. And other people touch those and get viruses that way."
Health officials recommend that people sneeze into their elbow. Using a tissue or handkerchief is another preferred option.
The study was presented Monday at an infectious diseases conference in Atlanta.
The Associated Press contributed to this report.