Preventing the Spread of Infectious Disease IS IN YOUR HANDS. The single most effective way to prevent the spread of infectious disease, including COVID-19, is to wash your hands often and well. At work, promoting good hygiene, aside from having people stay home when they’re sick, is your best defense. Scrub for 20 seconds, lathering the front, back, fingertips, behind the nails, and between your fingers. To be proactive, skip handshakes and use a tissue or cloth to open door handles. Promote good hand hygiene at work with downloadable posters on resources.