A wide variety of viruses and bacteria can cause tonsillitis, so the best prevention is to follow basic health and hygiene precautions. These steps are especially helpful for children: 1  Avoid close contact with others who are sick. Avoid close contact with others who are sick. 2  If possible, keep your child away from children who are known to have tonsillitis or a sore throat. 3  Often remind your child about the importance of proper hand-washing, especially when around people who appear to be sick.