This may have public health implications, as strategies for preventing infection include vaccination, simple hygiene, and, in the case of toxoplasmosis, antibiotics. Based on studies in animal models, theoretical concerns have been raised about a possible link between schizophrenia and maternal immune response activated by virus antigens; a 2009 review concluded that there was insufficient evidence to recommend routine use of trivalent influenza vaccine during the first trimester of pregnancy, but that the vaccine was still recommended outside the first trimester and in special circumstances such as pandemics or in women with certain other conditions. The CDC's Advisory Committee on Immunization Practices, the American College of Obstetricians and Gynecologists, and the American Academy of Family Physicians all recommend routine flu shots for pregnant women, for several reasons: their risk for serious influenza-related medical complications during the last two trimesters; their greater rates for flu-related hospitalizations compared to non-pregnant women; the possible transfer of maternal anti-influenza antibodies to children, protecting the children from the flu; and several studies that found no harm to pregnant women or their children from the vaccinations. Despite this recommendation, only 16% of healthy pregnant US women surveyed in 2005 had been vaccinated against the flu. Ingredient concerns Aluminum compounds are used as immunologic adjuvants to increase the effectiveness of many vaccines. The aluminum in vaccines simulates or causes small amounts of tissue damage, driving the body to respond more powerfully to what it sees as a serious infection and promoting the development of a lasting immune response. In some cases these compounds have been associated with redness, itching, and low-grade fever, but the use of aluminum in vaccines has not been associated with serious adverse events. In some cases, aluminum-containing vaccines are associated with macrophagic myofasciitis (MMF), localized microscopic lesions containing aluminum salts that persist for up to 8 years. However, recent case-controlled studies have found no specific clinical symptoms in individuals with biopsies showing MMF, and there is no evidence that aluminum-containing vaccines are a serious health risk or justify changes to immunization practice. Infants are exposed to greater quantities of aluminum in daily life in breastmilk and infant formula than in vaccines. In general, people are exposed to low levels of naturally occurring aluminum in nearly all foods and drinking water. The amount of aluminum present in vaccines is small, less than one milligram, and such low levels are not believed to be harmful