Common side effects of Xolair include a reaction at the injection site, viral infections, upper respiratory tract infection, sinusitis, headache, sore throat, pain, dizziness, nausea and vomiting. These side effects were about as common in patients who received placebo injections. Several rare, yet severe side effects were reported in the original studies. They include malignancy and anaphylaxis. In the initial studies, cancers (including breast, skin, prostate and salivary gland) were seen in 0.5 percent (20 of 4127) of patients treated with Xolair. The rate was 0.2 percent (5 of 2236) in patients treated with the placebo dose. A subsequent 5-year study of 5007 Xolair treated and 2829 non-Xolair treated adolescent and adult patients found similar rates of primary cancers (per 1000 patient years) in each group (12.3 compared to 13.0 respectively). In the initial studies, anaphylaxis was seen in less than 0.1 percent of the patients treated with Xolair. Since Xolair was approved in June 2003, additional reports of anaphylaxis have been reported to the FDA. Information was gathered from about 57,300 patients treated with Xolair (from June 2003-December 2006). The reaction rate was estimated to be 0.1 percent and at least 0.2 percent. The serious reactions occurred in at least 1 of every 1,000 patients. The reactions these patients had included combinations of symptoms of anaphylaxis.