Many infections can be caused due to high-risk sexual behavior. These are known as'sexually transmitted infection (STI). These can be bacterial viral parasitic commonly.
Among many infections, only two are preventable by use of vaccines, HPV (Human Papilloma Virus) and Hepatitis B Virus. It is best to take them before the onset of sexual activity. However, something is better than nothing. So even after the start of sexual life, one can get these. Both vaccines have three injections in the first 6 months.