Recent infection testing algorithm (RITA) applied to new HIV diagnoses in England, Wales and Northern Ireland, 2009 to 2011

Euro Surveill. 2014 Jan 16;19(2):20673. doi: 10.2807/1560-7917.es2014.19.2.20673.

Abstract

In 2009, Public Health England (PHE) introduced the routine application of a recent infection testing algorithm (RITA) to new HIV diagnoses, where a positive RITA result indicates likely acquisition of infection in the previous six months. Laboratories submit serum specimens to PHE for testing using the HIV 1/2gO AxSYM assay modified for the determination of HIV antibody avidity. Results are classified according to avidity index and data on CD₄ count, antiretroviral treatment and the presence of an AIDS-defining illness. Between 2009 and 2011, 38.4% (6,966/18,134) of new HIV diagnoses in England, Wales and Northern Ireland were tested. Demographic characteristics of those tested were similar to all persons with diagnosed HIV. Overall, recent infection was 14.7% (1,022/6,966) and higher among men who have sex with men (MSM) (22.3%, 720/3,223) compared with heterosexual men and women (7.8%, 247/3,164). Higher proportions were among persons aged 15-24 years compared with those ≥50 years (MSM 31.2% (139/445) vs 13.6% (42/308); heterosexual men and women 17.3% (43/249) vs 6.2% (31/501)). Among heterosexual men and women, black Africans were least likely to have recent infection compared with whites (4.8%, 90/1,892 vs 13.3%, 97/728; adjusted odds ratio: 0.6; 95% CI: 0.4-0.9). Our results indicate evidence of ongoing HIV transmission during the study period, particularly among MSM.

MeSH terms

  • Adolescent
  • Adult
  • Age Distribution
  • Algorithms*
  • CD4 Lymphocyte Count
  • Contact Tracing / methods*
  • England / epidemiology
  • Epidemiological Monitoring
  • Female
  • HIV Infections / diagnosis*
  • HIV Infections / epidemiology
  • HIV Infections / transmission*
  • Heterosexuality / statistics & numerical data
  • Homosexuality, Male / statistics & numerical data
  • Humans
  • Male
  • Middle Aged
  • Northern Ireland / epidemiology
  • Odds Ratio
  • Population Surveillance
  • Sex Distribution
  • Wales / epidemiology
  • Young Adult