14th Annual Conference of the British HIV Association 23–25 April 2008, Belfast

DIAGNOSING THE UNDIAGNOSED: IDENTIFYING SYMPTOMATIC PRIMARY HIV INFECTION (PHI) PRESENTING TO PRIMARY AND EMERGENCY HEALTHCARE PHYSICIANS

HIV Med 2008; 9(Suppl. 1):2 (abstract no. O5)

K Nambiar¹, D Pao¹, J Whetham¹, D Sudarshi¹, G Homer¹, G Murphy², J Parry² and M Fisher^1
1Brighton and Sussex University Hospitals, Brighton, UK, ²Health Protection Agency, London, UK

BACKGROUND: Identifying undiagnosed PHI remains a significant challenge. Individuals with PHI play a key role in the transmission of HIV, particularly in men who have sex with men. A previous study suggested that PHI symptoms are often missed in primary or emergency care. The aim of this study was to prospectively determine the prevalence of undiagnosed PHI in symptomatic individuals.

DESIGN: Unlinked, anonymous HIV testing of males aged from 18 to 50 with typical PHI symptoms (excluding known HIV infection) in local GP practices and an Accident and Emergency Department from January 2006 to June 2007.

METHODS: Residual sera were taken from Full Blood Count (FBC) or Glandular Fever serology (GF) samples. Screening was by pooled HIV-1 RNA testing in parallel with a 4th generation antigen/antibody assay. Incident infection was determined using STARHS (Serological Testing Algorithm for Recent HIV Seroconversion) or Western Blot assay.

RESULTS: 686 subjects were tested -587 (86%) FBC and 99 (14%) GF. 7 were HIV positive giving an overall prevalence of 1% (95% CI 0.3 – 1.7). Only one (0.1%) showed evidence of PHI (Antibody negative, Western Blot p24 only, Viral load 34,093,556 copies/mL). No case of PHI was detected using pooled RNA testing alone.

DISCUSSION: The PHI prevalence is substantially lower than expected. This may be due to patients not being venesected if an unspecified viral illness is suspected. It therefore remains essential that physicians are vigilant for symptoms of possible PHI and have a low threshold to test for HIV, particularly in high risk groups. The overall 1% undiagnosed HIV prevalence, however, suggests that more widespread testing in primary/ emergency care may be warranted.

2008-04-23
O5

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