DNA vaccine sterilizes mice, could lead to one-shot birth control

Animal birth control could soon be just a shot away: A new injection makes male and female mice infertile by tricking their muscles into producing hormone-blocking antibodies.

If the approach works in dogs and cats, researchers say, it could be used to neuter and spay pets and to control reproduction in feral animal populations. A similar approach could one day spur the development of long-term birth control options for humans.

For decades, the go-to methods for controlling animal reproduction have been spay or neuter surgeries. But the surgeries, which require animals to be anesthetized, can be expensive—one reason so many dogs and cats remain unfixed and feral animal populations continue to grow. Nearly 2.7 million dogs and cats were euthanized in U.S. shelters last year. A cheaper, faster method of sterilization is considered a holy grail for animal population control.

Biologist Bruce Hay of the California Institute of Technology in Pasadena and colleagues took a specific approach to blocking gonadotropin-releasing hormone (GnRH). Rather than rely on animals’ immune systems to create antibodies, he and his colleagues engineered a piece of DNA that—when packaged inside inactive virus shells and injected into mice—turned their muscle cells into anti-GnRH antibody factories. Because muscle cells are some of the longest lasting in the body, they continue to churn out the antibodies for 10 or more years.

Joyce Briggs, president of the Alliance for Contraception in Cats and Dogs, says that “a long-term contraceptive with a duration of 10 years could be a true game changer for dog and cat welfare.