Towards Targeted Screening for Acute HIV Infections in British Columbia

Background: Our objective was to describe the characteristics of acute and established HIV infections diagnosedin the Canadian province of British Columbia. Province-wide HIV testing and surveillance data were analyzed toinform recommendations for targeted use of screening algorithms to detect acute HIV infections.Methods: Acute HIV infection was defined as a confirmed reactive HIV p24 antigen test (or HIV nucleic acid test), anon-reactive or reactive HIV EIA screening test and a non-reactive or indeterminate Western Blot. Characteristics ofunique individuals were identified from the British Columbia HIV/AIDS Surveillance System. Primary drug resistanceand HIV subtypes were identified by analyzing HIV pol sequences from residual sera from newly infectedindividuals.Results: From February 2006 to October 2008, 61 individuals met the acute HIV infection case definition,representing 6.2% of the 987 newly diagnosed HIV infections during the analysis period. Acute HIV infection caseswere more likely to be men who have sex with men (crude OR 1.71; 95% CI 1.01-2.89], to have had a documentedprevious negative HIV test result (crude OR 2.89; 95% CI 1.52-5.51), and to have reported a reason for testing dueto suspected seroconversion symptoms (crude OR 5.16; 95% CI 2.88-9.23). HIV subtypes and rates of transmitteddrug resistance across all classes of drugs were similar in persons with both acute and established HIV infections.Conclusions: Targeted screening to detect acute HIV infection is a logical public health response to the HIVepidemic. Our findings suggest that acute HIV infection screening strategies, in our setting, are helpful for earlydiagnosis in men who have sex with men, in persons with seroconversion symptoms and in previously negativerepeat testers.