There is no known prevention for CLL.
Sometimes CLL can be become very active very quickly. Most of the time, however, CLL grows very slowly over a number of years. As CLL becomes more active, it will gradually weaken the person and cause serious problems. When the person begins to have symptoms, such as infection or swelling lymph nodes, he or she needs to be treated. Without treatment, active CLL can cause death.
CLL is not contagious and poses no risk to others.