title: Detection of new HIV infections in a multicentre HIV antiretroviral pre-exposure prophylaxis trial.
abstract: Monthly specimens collected from FEM-PrEP-a Phase III trial [1] were investigated for the detection of acute HIV (AHI) infection.
  
  
  
  To evaluate the efficiency of the study-specific HIV algorithm in detecting AHI, and the performance of each of the serological and molecular tests used in diagnosing new infections, and their contribution to narrowing the window period.
  
  
  
  A total of 83 pre-seroconversion specimens from 61 seroconverters from the FEM-PrEP trial were further analyzed in a sub-study. During the trial, HIV seroconversion was diagnosed on site using a testing algorithm with simple/rapid tests (SRTs) and confirmed with a gold standard testing algorithm (see short communication: Fig. 1). The infection date was determined more accurately by the use of standard ELISAs and Nucleic Acid Amplification Tests (NAAT) in a look-back procedure. For this sub-study, the international central laboratory repeated the study algorithm using SRTs.
  
  
  
  A total of 83 pre-seroconversions specimens from 61 seroconverters were analyzed in a look-back procedure. RNA was detected in 35/61 seroconverters at the visit before the seroconversion visit as determined at the study sites. Four seroconversion dates were inaccurate at one study site as the international central laboratory detected the HIV infection one visit earlier using the same test algorithm. Using the gold standard, an additional seroconversion was detected at an earlier visit. The combined antigen/antibody and the single antigen test had a higher sensitivity compared to the SRTs in detecting acute infections.
  
  
  
  In the FEM-PrEP trial, the international central laboratory detected a small number of seroconversions one month earlier than the study sites using the same study algorithm. Standard tests are still the most sensitive tests in detecting pre-seroconversion or acute HIV infection, but they are costly, time consuming and not recommended for use on-site in a clinical trial.
authors.affiliation: Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Fransen
authors.affiliation: Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Irith
authors.initials: I
authors.lastname: de Baetselier
authors.affiliation: Setshaba Research Centre, Soshanguve, Pretoria, South Africa.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Rammutla
authors.affiliation: Setshaba Research Centre, Soshanguve, Pretoria, South Africa.
authors.forename: Khatija
authors.initials: K
authors.lastname: Ahmed
authors.affiliation: Impact Research and Development Organization, Kisumu, Kenya.
authors.forename: Frederick
authors.initials: F
authors.lastname: Owino
authors.affiliation: Impact Research and Development Organization, Kisumu, Kenya.
authors.forename: Walter
authors.initials: W
authors.lastname: Agingu
authors.affiliation: JOSHA Research, Bloemfontein, South Africa.
authors.forename: Gustav
authors.initials: G
authors.lastname: Venter
authors.affiliation: FHI 360, Durham, NC, USA.
authors.forename: Jen
authors.initials: J
authors.lastname: Deese
authors.affiliation: FHI 360, Durham, NC, USA; Bill and Melinda Gates Foundation, Seattle, Washington, USA.
authors.forename: Lut
authors.initials: L
authors.lastname: Van Damme
authors.affiliation: Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Tania
authors.initials: T
authors.lastname: Crucitti
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage*; D004311:Double-Blind Method; D004338:Drug Combinations; D000068679:Emtricitabine / Q000008:administration & dosage; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000517:prevention & control*; D006679:HIV Seropositivity; D015497:HIV-1 / Q000235:genetics / Q000276:immunology; D006801:Humans; D065129:Pre-Exposure Prophylaxis; D000068698:Tenofovir / Q000008:administration & dosage
chemical_list: D019380:Anti-HIV Agents; D004338:Drug Combinations; D000068698:Tenofovir; D000068679:Emtricitabine
keywords: Early HIV diagnosis; HIV testing algorithm; HIV window period; Simple rapid tests