Vaccination. A child being vaccinated. The vaccine being given is the third and final dose of the SPf66 synthetic malaria vaccine in its first field trial. Malaria is carried by a parasitic protozoan carried in the saliva of Anopheles mosquitoes. Symptoms include severe chills and fever, and in some cases liver, kidney, blood and brain complications which can be fatal. Malaria parasites are becoming increasingly resistant to antimalarial drugs so the development of an effective vaccine could be very important in controlling the spread of the disease. Of the 1.8 billion people at risk of malaria worldwide, 200 million become infected each year.