WEDNESDAY, June 26 (HealthDay News) -- Children, teachers and health workers are among those at greatest risk for catching and transmitting flu-type infections based on the amount of contact they have with others, a new study finds.

British researchers ranked the risk of more than 5,000 people according to their number of daily interactions, determined through online and mail surveys. Social contacts were defined as face-to-face conversations within 6.5 feet or skin-on-skin physical touch.

"People working as teachers or health professionals are no doubt already aware that they have higher risks of picking up bugs like colds and flu. But before this study there was very little data mapping out the contact patterns humans have in their daily life," Leon Danon, from the Mathematics Institute at the University of Warwick, England, said in a university news release.


"By quantifying those social interactions, we can better predict the risks of contracting and spreading infections and ultimately better target epidemic control measures in the case of pandemic flu, for example," he explained.

Children had the highest number of social contacts. Adults with the highest number of social contacts worked in schools, the health sector and stores and other outlets that dealt with customers. Older students, unemployed people and retirees had the lowest levels of social contacts.

For example, teachers see an average of 62 people during a working day, while a retiree sees 19 people a day, according to the study, published June 27 in the journal Proceedings of the Royal Society B.

How much time someone is in contact with other people is another important factor in the risk of catching or transmitting infections, so the researchers also calculated "contact hours" experienced in a given day. Most people have an average of about 26 social contact hours a day, but those who spend time with a number of people simultaneously have up to 50 contact hours per day.

For example, children have an average of more than 47 contact hours per day, compared with about 33 for a health worker, 32 for a teacher, and 19 for a retiree.

The hours of social contact tend to decline with age, but there is a noticeable increase in social contact hours among people ages 35 to 45, which may be due to having school-age children, the researchers said.

People in high-contact occupations can reduce the risk of catching or spreading infections by regularly washing their hands with soap and water, keeping surfaces clean and using tissues when they cough or sneeze, the researchers said.

More information

The U.S. Department of Health and Human Services explains how to protect yourself from seasonal flu.