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Short report
HIV seroconversion among Baltimore City residents tested at a mobile van programme
  1. Sarah Puryear1,
  2. Phyllis Burnett2,
  3. Kathleen R Page2,3,
  4. Ravikiran Muvva2,
  5. Patrick Chaulk2,3,4,
  6. Khalil G Ghanem3,
  7. Anne Monroe5
  1. 1 Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
  2. 2 Baltimore City Health Department, Baltimore, Maryland, USA
  3. 3 Division of Infectious Diseases, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
  4. 4 Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
  5. 5 Division of General Internal Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
  1. Correspondence to Dr Anne Monroe, Division of General Internal Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA; amonroe4{at}


Background Many individuals with HIV in the USA are unaware of their diagnosis, and therefore cannot be engaged in treatment services, have worse clinical outcomes and are more likely to transmit HIV to others. Mobile van testing may increase HIV testing and diagnosis. Our objective was to characterise risk factors for HIV seroconversion among individuals using mobile van testing.

Methods A case cohort study (n=543) was conducted within an HIV surveillance dataset of mobile van testing users with at least two HIV tests between September 2004 and August 2009 in Baltimore, Maryland. A subcohort (n=423) was randomly selected; all additional cases were added from the parent cohort. Cases (n=122 total, two from random subcohort) had documented seroconversion at the follow-up visit. A unique aspect of the analysis was use of Department of Corrections data to document incarceration between the times of initial and subsequent testing. Multivariate Cox proportional hazards models were used to compare HIV transmission risk factors between individuals who seroconverted and those who did not.

Results One hundred and twenty-two HIV seroconversions occurred among 8756 individuals (1.4%), a rate higher than that in Baltimore City Health Department’s STD Clinic clients (1%). Increased HIV seroconversion risk was associated with men who have sex with men (MSM) (HR 32.76, 95% CI 5.62 to 191.12), sex with an HIV positive partner (HR 70.2, 95% CI 9.58 to 514.89), and intravenous drug use (IDU) (HR 5.65, 95% CI 2.41 to 13.23).

Conclusions HIV testing is a crucial first step in the HIV care continuum and an important HIV prevention tool. This study confirmed the need to reach high-risk populations (MSM, sex with HIV-positive individuals, individuals with IDU) and to increase comprehensive prevention services so that high-risk individuals stay HIV uninfected. HIV testing in mobile vans may be an effective outreach strategy for identifying infection in certain populations at high risk for HIV.

  • HIV
  • mobile van testing
  • seroconversion
  • men who have sex with men (MSM)
  • intravenous drug use (IDU)

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  • Handling editor Jackie A Cassell

  • Contributors SP contributed to research question development, conduct of analyses and wrote the initial draft of the manuscript. PB, KP, RM and PC designed and directed the testing programme and oversaw data collection, contributed to research question development and performed critical revision. KG contributed to design of analyses, manuscript writing and critical revision. AM conducted research question development, design and conduct of analyses, manuscript writing and critical revision. All authors contributed to the writing and have approved the final manuscript.

  • Funding AM is supported by NIMH K23MH105284-01.

  • Competing interests None declared.

  • Ethics approval Johns Hopkins Medicine IRB, Number NA_00002614

  • Provenance and peer review Not commissioned; externally peer reviewed.