Yellow fever as well as larvae-eating fish and copepods, which reduce the number of larvae. For many years, copepods of the genus "Mesocyclops" have been used in Vietnam for preventing dengue fever. It eradicated the mosquito vector in several areas. Similar efforts may be effective against yellow fever. Pyriproxyfen is recommended as a chemical larvicide, mainly because it is safe for humans and effective even in small doses. The second strategy is to reduce populations of the adult yellow fever mosquito. Lethal ovitraps can reduce "Aedes" populations, but with a decreased amount of pesticide because it targets the mosquitoes directly. Curtains and
Yellow fever vaccine of age. Those travelling to areas where the disease occurs should also be immunized. Additional doses after the first are generally not needed. Yellow fever vaccine is generally safe. This includes in those with HIV infection but without symptoms. Mild side effects may include headache, muscle pains, pain at the injection site, fever, and rash. Severe allergies occur in about eight per million doses, serious neurological problems occur in about four per million doses, and organ failure occurs in about three per million doses. It is likely safe in pregnancy and therefore recommended among those who will be potentially exposed.