Detection of recent HIV infections in African individuals infected by HIV-1 non-B subtypes using HIV antibody avidity

Barbara Suligoi, Stefano Buttò, Claudio Galli, Daniela Bernasconi, Robert A. Salata, Lara Tavoschi, Michele Chiappi, Peter Mugyenyi, Fulvia Pimpinelli, Cissy Kityo, Vincenza Regine, Giovanni Rezza

Research output: Contribution to journalArticlepeer-review


Background: To estimate HIV incidence several methods have been used to discriminate recent HIV infections from long-standing infections using a single serum sample. Objective: To evaluate the performance of the anti-HIV avidity index (AI) for identifying recent HIV infections in individuals with a known date of seroconversion from Uganda, where the predominant HIV subtypes are A and D. Study design: We selected 149 repository serum samples from Ugandan HIV-positive individuals and evaluated the AI. Specimens collected ≤6 months after seroconversion were considered as recent infections, and those collected >6 months as long-standing infections. All specimens were serotyped using a V3 peptide enzyme immunoassay. Results: The mean AI was 0.55 ± 0.21 among the 108 patients with recent infections and 0.93 ± 0.14 among the 41 samples from long-standing infections (p <0.0001). The AI test showed a sensitivity of 85.2% and a specificity of 85.4% at a cutoff of 0.80. No significant association was observed between serotype and the misclassification of samples by AI. Conclusions: The AI, which is inexpensive and easy-to-perform, can be useful in identifying recent HIV infections in countries where HIV-1 non-B subtypes are prevalent.

Original languageEnglish
Pages (from-to)288-292
Number of pages5
JournalJournal of Clinical Virology
Issue number4
Publication statusPublished - Apr 2008


  • Africa
  • AIDS
  • Antibody avidity
  • HIV
  • Incidence

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Virology
  • Immunology and Allergy
  • Infectious Diseases


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