A vaccine against human malaria--an utopia?

At the beginning of the 1980s, the future of the malaria vaccines looks bright; in recent years a number of basic problems have been solved. Among the major landmarks have been the discovery of a suitable animal model for human malaria infections; the technique of culturing Plasmodium falciparum; the findings that sporozoites, merozoites and gametocytes, or possibly antigens characterized with the hybridoma technique, can be used as vaccine antigens at least in animals; and that excellent protection from fatal disease is obtainable in owl monkeys by using the merozoite vaccine with a suitable adjuvant. Many questions remain still unanswered. The foremost, of course, is whether the vaccine(s) is efficient in humans. Other major problems still existing are identification, characterization and purification of the protective antigen(s) of human malarias, assessment of the clinical effects of the vaccines produced, new methods for the mass production of the antigens, and studies on duration of the clinical protection.