Primary HIV Infection

Nick Gazy1 and Anthony D Kelleher1,2

1. Dept of HIV and Immunology, St Vincent’s Hospital, Darlinghurst, NSW

2. Kirby Institute, UNSW Sydney



Primary HIV infection (PHI) usually refers to the critical six-month period following the acquisition of HIV. This period, immediately following initial infection, is associated with a highly dynamic series of virological and immunological events, which have been demonstrated to impact the long-term course of untreated infection, including severity and rate of disease progression. It is now recognised as the ideal time to commence anti-retroviral therapy (ART). Clinically, the initial stages of infection are characterised by a ‘mononucleosis-like’ illness that is non-specific and generally mild but with characteristic clinical manifestations. Recognition of these signs and symptoms provides a clue to diagnosis, providing an opportunity for subsequent rapid initiation of ART.

The early weeks following HIV infection may also be variously referred to as acute seroconversion illness, acute HIV infection, or the acute retroviral syndrome. Clinicians must have a high index of suspicion for PHI in people who are known to have a high-risk of acquiring sexually-transmissible or blood-borne virus infections and/or people that present with consistent symptoms, as well as the clinical acumen to arrange appropriate screening and diagnostic testing.

 Early diagnosis in this critical period is of great importance, both from a public health perspective, with rates of transmission highest during PHI, and for the individual, as early initiation of ART is now well established to be beneficial by positively modifying long-term disease outcomes and by limiting both immune damage and the size of the viral reservoir with reduction of onwards transmission.