The phrase "to spread the infection" means that a disease or illness is being passed from one person to another, causing more people to become sick. Full definition
Teaching acceptable hygiene principles is vital to creating life long habits, which will in turn, prevent illness and reduce the risk of spreading infection in years to come. (educationbusinessuk.net)
Getting Boots into the examination room right away helps prevent spreading the infection in the waiting area and throughout the hospital. (aaha.org)
It's also important to wash your hands often, especially before and after you examine your baby's eyes, to avoid spreading the infection. (babycenter.com)