Primary HIV infection encompasses the biological and clinical manifestations of the period between initial contact with the virus and the appearance of specific antibodies.1 #### Case scenario A previously healthy 19 year old man was admitted to our medical ward with a history of fever, sore throat, and a maculopapular rash on his trunk. An upper respiratory tract infection had been diagnosed in the community a few days before. A monospot test (for infectious mononucleosis caused by Epstein-Barr virus) was negative, and he initially denied risky sexual behaviour and declined an offer of HIV testing. His symptoms improved, but before discharge he mentioned to the ward sister that he had had a casual sexual encounter with a man a few weeks earlier. He then consented to an HIV test, which was positive for the p24 antigen. #### How common is primary HIV infection?2 Primary HIV infection is symptomatic in most individuals but is easy to miss.3 4 In a …