Q. Is there a vaccine to prevent human immunodeficiency virus (HIV)?
A. No, although researchers have been working to design a vaccine for many years, vaccine development has been difficult. HIV changes rapidly as it replicates in even a single individual. This makes HIV difficult to prevent because immunity provided by a vaccine against a previous version of the virus may be ineffective against a newer version of the virus.
Learn more or print “Special Topics: Human Immunodeficiency Virus” [PDF, 629KB].