The Centre Against Sexual Assault also provides referal for medical follow-up. An important part of this is screening for sexually transmitted infections although the risk of catching one from a sexual assault is not high. You will need follow-up medical visits, 2 weeks, 6 weeks and 12 weeks after the assault to eliminate the possibility of infection. The tests include screening for HIV, the AIDS virus. Until you receive the results of all the tests you may wish to practice safe sex, by avoiding contact in which semen, vaginal fluids or blood pass from one person to another.