This idea is controversial. “I’ve always felt that people don’t do enough to prevent cold and flu, and so in a sense many of these changes have been healthy,” says Jo Handelsman, an infectious-disease researcher and professor at the University of Wisconsin-Madison. She says it’s unclear whether shaking hands or spending time in crowded places meaningfully contributes to microbiome health, and so avoiding such risky practices may be all upside — a view that many infectious disease experts share.
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