The most effective way to prevent sexually transmitted infections is
- A. taking an antibiotic after every possible exposure
- B. vaccination, since a vaccine exists for every such infection
- C. washing thoroughly after exposure
- D. avoiding contact with infected persons and using barrier protection
Explanation
Prevention works by stopping the exchange of infected body fluids, so avoiding contact with an infected person and using a barrier are what actually reduce risk, together with screened blood and sterile needles. Taking antibiotics after exposure treats nothing viral and encourages resistance. Vaccines exist for hepatitis B and human papillomavirus but not for gonorrhoea, syphilis, herpes or HIV.