Common transfer factor side effects include pain and swelling at the injection site, according to WebMD. Some people also experience fever. Medical experts believe that transfer factor is potentially safe for up to six years in children and up to two years in adults.
Medical practitioners give transfer factors to people suffering from bacterial or viral infections and those with compromised immune systems, says WebMD. The treatable infections range from flu and hepatitis B to Epstein-Barr virus and Mycobacterium tuberculosis. Doctors also use transfer factors to combat infertility, fibromyalgia, diabetes, skin conditions and eye conditions, as well as Lou Gehrig's disease and other autoimmune diseases, asthma and cancers of the bone, lung and skin.
As of 2015, transfer factor has been shown to possibly work in cases of shingles, according to WebMD. An injection of transfer factor protects children with leukemia from a first bout of shingles. It does not seem to prevent a second occurrence of shingles and does not seem to be effective in preventing shingles in leukemia patients who have received bone marrow transplants. However, when given to people who have shingles, transfer factor seems to ease the painful symptoms.
Transfer factors probably do not work against cancer, Lou Gehrig's disease and multiple sclerosis, explains WebMD. There is also not enough evidence of the drugs' effectiveness in cases of acne, asthma, eczema, chronic fatigue syndrome and other disorders.