Immunization against HCG

The possibility of using the immune system to provide protection against an unwanted pregnancy has been postulated since the very early days of modern immunology. During the past two decades or more, a major goal-directed research effort, involving several independent groups of investigators, has been underway with the objective of developing birth control vaccines suitable for use by men and women at all stages of their reproductive lives. The most advanced work in this area is concerned with the development of a vaccine directed against human chorionic gonadotrophin (HCG), a hormone that is produced by the peri-implantation embryo and that is essential for successful implantation and the establishment of early pregnancy. These studies have reached the stage of clinical testing of a number of prototype vaccines based on different parts of the HCG molecule. No adverse side effects have been observed or reported in these clinical trials and larger scale clinical studies are being planned to assess further the safety, efficacy and acceptability of these preparations. Research is also underway to develop improved versions of these HCG vaccines that will offer 12-18 months protection following a single injection. The stage is set for the introduction, by the turn of this century, of the first totally new method of family planning in four decades.