Contraceptive vaccine reduces fertility in animals to address wildlife overpopulation
Patent-pending vaccine stimulates lasting immune response that addresses limitations of current models
15 June 2026
1 minute read
By: A Purdue University contraceptive vaccine seeks to address animal overpopulation by markedly reducing fertility in feral swine, horses, deer and other animals.
Dr. Harm HogenEsch, distinguished professor of immunopathology in Purdue University’s College of Veterinary Medicine, and Dr. Raluca Ostafe, director of Purdue University’s Molecular Evolution Protein Engineering and Production Facility, have designed the vaccine based on the IZUMO1 mammalian sperm protein. It induces a robust and long-lasting immune response and infertility in female mammals.
The research has been published in the Feb. 6 issue of the peer-reviewed journal Vaccine.
“Attempts to make an effective vaccine against sperm proteins have failed or only had modest success,” HogenEsch said. “Our vaccine overcomes the limitations of existing contraceptive vaccines.”
Drawbacks of traditional contraceptive vaccines
There are currently two types of contraceptive vaccines, both based on self-proteins, which require a breakdown of immune tolerance.
HogenEsch said these vaccines have several drawbacks:
They reduce fertility, but the effect is not long-lasting.
They are associated with injection site reactions ranging from swelling to abscesses.
One vaccine targets hormones that could cause behavioral changes.
One vaccine is prepared from sources that are at risk to supply chain interruptions.
HogenEsch’s contraceptive vaccine addresses these limitations.
“It is based on a male sperm protein that the female’s immune system recognizes as foreign,” he said. “It works exclusively by inhibiting the fusion of a sperm cell and the oocyte. The vaccine consists of a well-defined peptide produced in mammalian cells and an effective and safe adjuvant.”
Validation and next development steps
The successful production and purification of the Purdue vaccine were validated via Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and western blot analysis of the proteins. Its ability to reduce fertility was experimentally observed by injecting different formulations into experimental groups; vaccination reduced fertility 59% to 67% overall.
HogenEsch plans to conduct further research into the contraceptive vaccine.
“We will develop it into a single-dose, controlled-release formulation. This is critical to the use of the vaccine in wildlife where giving a second dose to an animal is often very difficult if not impossible. A vaccine that induces long-lasting infertility with a single injection will greatly facilitate the utility of the vaccine,” he said. “We are also working to further optimize the design of the vaccine to allow delivery via darts and oral delivery.”
