Are All Those Handshakes at Graduation Hazardous to Your Health?

No, say researchers who found only harmless bacteria on students' hands in 93% of cases

FRIDAY, May 20 (HealthDay News) -- One graduation ceremony may include thousands of handshakes, but new research shows this casual contact is not likely to increase your risk of exposure to harmful bacteria.

Maryland students who shook a total of 5,209 hands while graduating from schools across the state in 2008 had only a slight risk of acquiring disease-causing bacteria, according to research from scientists at the Johns Hopkins Bloomberg School of Public Health.

The study examined the risk of acquiring pathogenic bacteria such as Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) through shaking hands at graduation ceremonies ranging from elementary school to college. Researchers swabbed participants' hands before and immediately following graduation to identify any disease-causing (pathogenic) bacteria. They detected only three instances of Staphylococcus aureus out of the thousands of handshakes -- a rate of 0.019 pathogens per handshake -- and found that 93 percent of the bacteria were harmless.

The study is in the June issue of the Journal of School Nursing.

"A single handshake offers only a small risk of acquiring harmful bacteria," said Dr. David Bishai, a professor with the Bloomberg School's department of population, family and reproductive health in a university news release. "Our study indicates when shaking hands, the rate of hand contamination among graduating students to be 100 times lower than the 17 percent rate observed among health workers caring for patients known to be colonized with MRSA."

Reasons for the lower rate of contamination at graduations include the "much briefer and less-extensive contact in a handshake" than contact with hospital patients, according to Bishai.

"Based on the evidence from this study, the probability of acquiring bacterial pathogens during handshaking could be lower than is commonly perceived by the general public," concluded Bishai. "With a lower bound estimate of one bacterial pathogen acquired in 5,209 handshakes, the study offers the politicians, preachers, principals, deans and even amateur hand shakers some reassurance that shaking hands with strangers is not as defiling as some might think."

More information

The U.S. Centers for Disease Control and Prevention offers tips on practicing proper hand hygiene.

Mary Elizabeth Dallas SOURCE: Johns Hopkins Bloomberg School of Public Health, news release, May 16, 2011

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