The Director of India's National Institute of Immunology began his research in the mid 1970s with financial support from the Indian government and IDRC.
Toxicology studies were conducted for 10 years. The vaccine increases production of antibodies against human chorionic gonadotropin (HCG), a hormone which assists in preparing the uterus for embryo implantation.
The vaccine blocks this process and prevents pregnancy. Without the vaccine, 50-75% of embryos fail to be implanted because of antibodies to HCG; with the vaccine, 100% do.
The vaccine is administered once a month for 3 months. Although another form of contraception must be used during this time, protection afterwards lasts for a year.
Boosters are given annually. In a clinical study of 88 vaccinated women, 1 pregnancy occurred in 821 menstrual cycles.
Fertility returns with discontinuation of the vaccinations. Dr Talwar is also working on a contraceptive for the 3-month period using the purified extract of the neem tree, a male contraceptive, a treatment for prostate cancer, and a vaccine against leprosy.