Before this vaccine can be approved, the FDA must be clear about its safety and efficacy. Both Gardasil and Cervarix have been tested in tens of thousands of humans in the United States and other countries, and so far no serious adverse reactions have been found. The most common problems have been pain and local reactions at the injection site. This article describes: the phenomenon is no different than with other vaccinations. There is not enough evidence that it is safe in pregnancy, and therefore, vaccination is not advocated during pregnancy. Recent safety reviews from the FDA and CDC concluded that serious side effects occurred when Gardasil was tested in safety trials prior to marketing, but the incidence was not different from other vaccines. However, venous thrombosis and syncope appear to occur more frequently than with other vaccines. The FDA and CDC remind healthcare providers that all vaccinated individuals need to sit or lie down for at least 15 minutes during vaccination to prevent falls and injuries.