Does were immunized with a contraceptive vaccine injected by tranquilizer guns.

Also, the current contraceptive vaccine must be readministered every year, but each year the darted does become a bit more wary and elusive, experts say.

Since 1993, this clearing has been an official baiting station in an experimental program to control the island's deer population with a contraceptive vaccine.

Scientists have produced an experimental contraceptive vaccine that prevents pregnancy in guinea pigs.

The program hopes to mass produce a contraceptive vaccine in Indonesia in 2013 at the earliest.

While contraceptive vaccines can be delivered remotely, they still require administration to each individual animal that is to be made infertile.

Thus contraceptive vaccines have been used to control only relatively small populations of wildlife.

This may be an issue for certain contraceptive vaccines.

The company, went public in 1993 with claims that a contraceptive vaccine was imminent.