Over the past [51] years, the WHO Task Force on Vaccines for Fertility Regulation has been supporting basic and clinical research on the development of birth control vaccines directed against the gametes or the preimplantation embryo. These studies have involved the use of advanced procedures in peptide chemistry, hybridoma technology and molecular genetics as well as the evaluation of a number of novel approaches in general vaccinology.
https://pubmed.ncbi.nlm.nih.gov/1874951/
1992 report
https://iris.who.int/bitstream/handle/10665/61301/WHO_HRP_WHO_93.1.pdf