The Birth Control Shot (commonly known as "Depo" or "Depo-Provera") is a kind of birth control that lasts for 3 months. It is injected into your body, either under your skin on into a muscle.
When used correctly (getting your shot on time and not missing shots) the shot is 99.9% effective at preventing pregnancy.
If you miss your birth control shot you may not be protected from pregnancy. Use a condom or don't have sex until you can get your next shot.
YES. The shot does NOT protect you against STDs and/or HIV. You should still use a condom for protection against these.