Peter D McElroy

Imperial College London, London, ENG, United Kingdom

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Publications (26)153.75 Total impact

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    ABSTRACT: HIV prevalence among state prison inmates in the United States is more than five times higher than among nonincarcerated persons, but HIV transmission within U.S. prisons is sparsely documented. We investigated 88 HIV seroconversions reported from 1988-2005 among male Georgia prison inmates. We analyzed medical and administrative data to describe seroconverters' HIV testing histories and performed a case-crossover analysis of their risks before and after HIV diagnosis. We sequenced the gag, env, and pol genes of seroconverters' HIV strains to identify genetically-related HIV transmission clusters and antiretroviral resistance. We combined risk, genetic, and administrative data to describe prison HIV transmission networks. Forty-one (47%) seroconverters were diagnosed with HIV from July 2003-June 2005 when voluntary annual testing was offered. Seroconverters were less likely to report sex (OR [odds ratio] = 0.02, 95% CI [confidence interval]: 0-0.10) and tattooing (OR = 0.03, 95% CI: <0.01-0.20) in prison after their HIV diagnosis than before. Of 67 seroconverters' specimens tested, 33 (49%) fell into one of 10 genetically-related clusters; of these, 25 (76%) reported sex in prison before their HIV diagnosis. The HIV strains of 8 (61%) of 13 antiretroviral-naïve and 21 (40%) of 52 antiretroviral-treated seroconverters were antiretroviral-resistant. Half of all HIV seroconversions were identified when routine voluntary testing was offered, and seroconverters reduced their risks following their diagnosis. Most genetically-related seroconverters reported sex in prison, suggesting HIV transmission through sexual networks. Resistance testing before initiating antiretroviral therapy is important for newly-diagnosed inmates.
    PLoS ONE 02/2009; 4(5):e5416. · 3.53 Impact Factor
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    ABSTRACT: Introduction: HIV prevalence among state prison inmates in the United States is more than five times higher than among nonincarcerated persons, but HIV transmission within U.S. prisons is sparsely documented. We investigated 88 HIV seroconversions reported from 1988-2005 among male Georgia prison inmates. Methods: We analyzed medical and administrative data to describe seroconverters' HIV testing histories and performed a case-crossover analysis of their risks before and after HIV diagnosis. We sequenced the gag, env, and pol genes of seroconverters' HIV strains to identify genetically-related HIV transmission clusters and antiretroviral resistance. We combined risk, genetic, and administrative data to describe prison HIV transmission networks. Results: Forty-one (47%) seroconverters were diagnosed with HIV from July 2003-June 2005 when voluntary annual testing was offered. Seroconverters were less likely to report sex (OR (odds ratio)=0.02, 95% CI (confidence interval): 0-0.10) and tattooing (OR=0.03, 95% CI: ,0.01-0.20) in prison after their HIV diagnosis than before. Of 67 seroconverters' specimens tested, 33 (49%) fell into one of 10 genetically-related clusters; of these, 25 (76%) reported sex in prison before their HIV diagnosis. The HIV strains of 8 (61%) of 13 antiretroviral-naive and 21 (40%) of 52 antiretroviral-treated seroconverters were antiretroviral-resistant. Discussion: Half of all HIV seroconversions were identified when routine voluntary testing was offered, and seroconverters reduced their risks following their diagnosis. Most genetically-related seroconverters reported sex in prison, suggesting HIV transmission through sexual networks. Resistance testing before initiating antiretroviral therapy is important for newly- diagnosed inmates.
    PLoS ONE 01/2009; 4(5). · 3.53 Impact Factor
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    ABSTRACT: HIV chemoprophylaxis may be a future prevention strategy to help control the global epidemic of HIV/AIDS. Safety and efficacy trials of two agents are currently underway. We assess the expected number of HIV cases prevented and cost-effectiveness of a hypothetical HIV chemoprophylaxis program among men who have sex with men in a large US city. We developed a stochastic compartmental mathematical model using HIV/AIDS surveillance data to simulate the HIV epidemic and the impact of a 5-year chemoprophylaxis program under varying assumptions for epidemiological, behavioral, programmatic and cost parameters. We estimated program effectiveness and costs from the perspective of the US healthcare system compared with current HIV prevention practices. The main outcome measures were number of HIV infections prevented and incremental cost per quality-adjusted life-years saved. A chemoprophylaxis program targeting 25% of high-risk men who have sex with men in New York City could prevent 780 (4%) to 4510 (23%) of the 19 510 HIV infections predicted to occur among all men who have sex with men in New York City in 5 years. More than half of prevented infections would be among those not taking chemoprophylaxis but who benefit from reduced HIV prevalence in the community. Under base-case assumptions, incremental cost was US$ 31 970 per quality-adjusted life-years saved. The program was cost-effective under most variations in efficacy, mechanism of protection and adherence. HIV chemoprophylaxis among high-risk men who have sex with men in a major US city could prevent a significant number of HIV infections and be cost-effective.
    AIDS (London, England) 10/2008; 22(14):1829-39. · 4.91 Impact Factor
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    ABSTRACT: Syphilis outbreaks among men who have sex with men (MSM) in the United States have raised concerns about increased HIV transmission in this population. We sought to estimate HIV incidence among men diagnosed with primary or secondary (P&S) syphilis in sexually transmitted disease (STD) clinics in Atlanta, San Francisco, and Los Angeles. We analyzed deidentified sociodemographic information from routine syphilis surveillance databases and matching remnant sera from consecutive male patients with P&S syphilis who were tested for syphilis at 3 public health laboratories during January 2004 through January 2006. Deidentified sera positive for Treponema pallidum by particle agglutination were screened for HIV-1 antibodies by enzyme immunoassay (EIA). Specimens that were confirmed HIV-positive by Western blot analysis were then tested for recent HIV infection using the less sensitive (LS) HIV-1 Vironostika EIA and BED HIV-specific IgG/total IgG assay. Of 357 men with P&S syphilis (98 in Atlanta, 151 in San Francisco, and 108 in Los Angeles), 32% had primary syphilis and 85% were MSM (12% no MSM risk and 3% no information). The median age was 36 years; 40% were white, 31% black, 20% Hispanic, and 8% other. Among men with P&S syphilis, 160 (45%) were HIV-positive, of whom 8 were classified as having acquired recent HIV infection by the LS-Vironostika EIA (all confirmed by BED) and had no history of antiretroviral use or HIV-positive results >6 months earlier. Seven of the 8 men with recent HIV infection were MSM. The estimated HIV incidence was 9.5% per year (95% confidence interval [CI]: 2.9 to 16.0) among all men and 10.5% per year (95% CI: 2.7 to 18.3) among MSM. We found high HIV incidence among a high-risk population of US men diagnosed with P&S syphilis in STD clinics in Atlanta, San Francisco, and Los Angeles. Intensive integrated HIV/STD prevention programs are needed for this population.
    JAIDS Journal of Acquired Immune Deficiency Syndromes 02/2008; 47(2):234-40. · 4.65 Impact Factor
  • PLoS Medicine 01/2008; In submission. · 15.25 Impact Factor
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    ABSTRACT: BACKGROUND:Social network analysis (SNA) is an innovative approach to the collection and analysis of infectious disease transmission data. We studied whether this approach can detect patterns of Mycobacterium tuberculosis transmission and play a helpful role in the complex process of prioritizing tuberculosis (TB) contact investigations. METHODS:We abstracted routine demographic and clinical variables from patient medical records and contact interview forms. We also administered a structured questionnaire about places of social aggregation to TB patients and their contacts. All case-contact, contact-contact, case-place, and contact-place dyads (pairs and links) were considered in order to analyze the structure of a social network of TB transmission. Molecular genotyping was used to confirm SNA-detected clusters of TB. RESULTS:TB patients not linked through conventional contact-investigation data were connected through mutual contacts or places of social aggregation, using SNA methods. In some instances, SNA detected connected groups prior to the availability of genotyping results. A positive correlation between positive results of contacts&apos; tuberculin skin test (TST) and location in denser portions of the person-place network was observed (P<.01). CONCLUSIONS:Correlation between TST-positive status and dense subgroup occurrence supports the value of collecting place data to help prioritize TB contact investigations. TB controllers should consider developing social network analysis capacity to facilitate the systematic collection, analysis, and interpretation of contact-investigation data.
    The Journal of Infectious Diseases 11/2007; 196(10):1517-1527. · 5.85 Impact Factor
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    ABSTRACT: We examined the feasibility and value of network analysis to complement routine tuberculosis (TB) contact investigation procedures during an outbreak. We reviewed hospital, health department, and jail records and interviewed TB patients. Mycobacterium tuberculosis isolates were genotyped. We evaluated contacts of TB patients for latent TB infection (LTBI) and TB, and analyzed routine contact investigation data, including tuberculin skin test (TST) results. Outcomes included number of contacts identified, number of contacts evaluated, and their TST status. We used network analysis visualizations and metrics (reach, degree, betweenness) to characterize the outbreak. secondary TB patients and more than 1200 contacts. Genotyping detected a 21-band pattern of a strain W variant. No HIV-infected patients were diagnosed. Contacts prioritized by network analysis were more likely to have LTBI than nonprioritized contacts (odds ratio=7.8; 95% confidence interval=1.6, 36.6). Network visualizations and metrics highlighted patients central to sustaining the outbreak and helped prioritize contacts for evaluation. A network-informed approach to TB contact investigations provided a novel means to examine large quantities of data and helped focus TB control.
    American Journal of Public Health 04/2007; 97(3):470-7. · 3.93 Impact Factor
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    Clinical Infectious Diseases 03/2007; 44(3):464-5; author reply 465. · 9.37 Impact Factor
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    ABSTRACT: Factors influencing tuberculosis cluster growth are poorly understood. The authors examined clusters of two or more culture-confirmed Mycobacterium tuberculosis cases between January 1, 2001, and December 31, 2003, that had insertion sequence 6110 (IS6110) restriction fragment length polymorphism and spoligotype patterns identical to those of another study case. Genotypes first seen in New York, New York, before or during 1993 were considered historical; recent strains were those first seen after 1993. The authors examined the effect of the combined characteristics of infectiousness of the first two cases in a cluster on the rate of cluster growth. Genotyping was performed for 2,408 (91.8%) of the 2,623 tuberculosis cases diagnosed; 873 cases were in 212 clusters. Thirty-one clusters had historical strains, 153 were recent, and 28 were of unknown period. Patients' infectiousness was not associated with the rate of cluster growth among historical strain clusters. Among recent strain clusters, infectiousness of both of the initial cases was associated with a higher rate of cluster growth compared with clusters in which neither initial case was infectious, upon adjustment for male sex (rate ratio = 2.62, 95% confidence interval: 1.19, 5.78). The rate of genotype cluster growth should be monitored regardless of how long the strain has been present in the community. However, infectiousness in the first two cases may be useful to prioritize genotype cluster investigations.
    American Journal of Epidemiology 08/2006; 164(1):21-31. · 4.78 Impact Factor
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    ABSTRACT: During 2002-2003, a large outbreak of tuberculosis (TB) occurred among persons using multiple homeless facilities in King County, Washington. To control the transmission of TB in multiple settings. In 2002, contacts exposed to patients in homeless facilities were screened using tuberculin skin tests (TSTs) and symptom review. Based on these screening results, sites of transmission were identified and prioritised, and exposed cohorts at these sites were offered intensive screening tests in 2003 (e.g., symptom review, TST, chest radiograph [CXR], sputum examination and culture). Mycobacterium tuberculosis isolates from patients were genotyped using PCR-based methods to identify outbreak-associated patients quickly. During 2002-2003, 48 (15%) of 313 patients diagnosed in King County were outbreak-associated; 47 culture-positive patients had isolates that matched the outbreak strain by genotyping. Three facilities visited by >12 patients in 2002 had a higher prevalence of TST positive results (approximately 30%) among clients compared with the background rate (7%) in the homeless community. Screening contacts with one sputum culture was as sensitive as CXR in detecting TB disease (77% vs. 62%, respectively). A comprehensive, resource-intensive approach likely helped to control transmission. This outbreak highlights the vulnerability of homeless populations and the need to maintain robust TB programs in urban settings.
    The International Journal of Tuberculosis and Lung Disease 06/2006; 10(6):683-9. · 2.76 Impact Factor
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    ABSTRACT: Severe liver injuries were attributed to the rifampin and pyrazinamide (RZ) regimen after it was recommended for treating latent tuberculosis infection. Implicating RZ as the likeliest cause required excluding alternative causes. US health departments reported data on patients who died or were hospitalized for liver disease within 1 month after taking RZ for latent tuberculosis infection from October 1998 through March 2004. The circumstances were investigated on site for each case. Illness characteristics, reasons for RZ treatment, doses and frequency of administration of pyrazinamide, monitoring during treatment, and causes of liver injury were determined. Liver injury was attributable to RZ use for all 50 patients reported, 12 of whom died. For 47 patients, RZ was the likeliest cause of liver injury. The median patient age was 44 years (range, 17-73 years). Thirty-two patients (64%) were male. Seven (16%) of 43 patients tested had hepatitis C virus antibodies, 1 (2%) of 45 had chronic hepatitis B, 3 (14%) of 22 had positive results of HIV serologic tests, 34 (71%) of 48 had alcohol use noted, and 33 (66%) of 50 were taking additional hepatotoxic medications. Six patients, 2 of whom died, had no predictors for liver disease. Patients who died were older (median age, 52 vs. 42 years; P=.08) and took a greater number of other medications (median number of medications, 4 vs. 2; P=.05) than did those who recovered, but these 2 factors were correlated (P<.01). Thirty-one patients (62%) were monitored according to guidelines, 9 of whom died. RZ was the likeliest cause of most of these liver injuries, some of which were fatal in spite of monitoring. Fatality was predicted by age or use of other medications, but none of the cofactors showed promise as a reliable clinical predictor of severe liver injury.
    Clinical Infectious Diseases 02/2006; 42(3):346-55. · 9.37 Impact Factor
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    ABSTRACT: The estimated prevalence of human immunodeficiency virus (HIV) infection is nearly five times higher for incarcerated populations (2.0%) than for the general U.S. population (0.43%). In 1988, the Georgia Department of Corrections (GDC) initiated mandatory HIV testing of inmates upon entry into prison and voluntary HIV testing of inmates on request or if clinically indicated. GDC offered voluntary HIV testing to inmates annually during July 2003-June 2005 and currently offers testing to inmates on request. During July 1988-February 2005, a total of 88 male inmates were known to have had both a negative HIV test result upon entry into prison and a subsequent confirmed positive HIV test result (i.e., seroconversion) during incarceration. Of these 88 inmates, 37 (42%) had had more than one negative HIV test result before their HIV diagnosis. In October 2004, GDC and the Georgia Division of Public Health invited CDC to assist with an epidemiologic investigation of HIV risk behaviors and transmission patterns among male inmates within GDC facilities and to make HIV prevention recommendations for the prison population. This report describes the results of that investigation, which identified the following characteristics as associated with HIV seroconversion in prison: male-male sex in prison, tattooing in prison, older age (i.e., age of >26 years at date of interview), having served > or =5 years of the current sentence, black race, and having a body mass index (BMI) of < or =25.4 kg/m2 on entry into prison. Findings from the investigation demonstrated that risk behaviors such as male-male sex and tattooing were associated with HIV transmission among inmates, highlighting the need for HIV prevention programs for this population.
    MMWR Morb Mortal Wkly Rep. 01/2006; 55(15):421-6.
  • JAMA The Journal of the American Medical Association 01/2006; 296(2):162-164. · 29.98 Impact Factor
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    Peter D. McElroy, Kashef Ijaz, Thomas R. Navin
    Clinical Infectious Diseases - CLIN INFECT DIS. 01/2006; 42(6):892-893.
  • Clinical Infectious Diseases 01/2006; 42(6):892-893. · 9.37 Impact Factor
  • J Am Med Assoc. 01/2006; 296(2):162-164.
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    ABSTRACT: Cases of severe and fatal liver injury were reported after a 2-month course of rifampin-pyrazinamide therapy was recommended in 2000 as an alternative to isoniazid for treatment of latent tuberculosis infection. We estimated rates of rifampin-pyrazinamide-associated liver injury and compared these with historical rates for isoniazid. We conducted a survey of state and city tuberculosis programs and other health care settings in the United States where rifampin-pyrazinamide was prescribed. The number of rifampin-pyrazinamide therapy initiations was collected, as well as the number of occurrences of (1) asymptomatic aspartate aminotransferase serum concentration >5 times the upper limit of normal, (2) symptomatic hepatitis (in which the patient was not hospitalized), (3) hospitalization for liver injury, (4) death with liver injury, and (5) treatment completion. We also searched a national pharmacy claims database (Verispan). Rates of these events were calculated. Among 139 programs, 110 (79%) responded; 87 (79%) had initiated rifampin-pyrazinamide therapy for a total of 8087 patients between January 2000 and June 2002. Rates per 1000 rifampin-pyrazinamide therapy initiations during this period were 25.6 (95% confidence interval [CI], 22.3-29.3) for asymptomatic aspartate aminotransferase level >5 times the upper limit of normal and 18.7 (95% CI, 15.9-21.9) for hepatitis. Seven fatalities and 23 hospitalizations occurred, with rates of 0.9 (95% CI, 0.4-1.9) and 2.8 (95% CI, 1.8-4.3) per 1000 rifampin-pyrazinamide therapy initiations, respectively. Of 8087 patients, 64% completed rifampin-pyrazinamide therapy. The Verispan search revealed 1 rifampin-pyrazinamide-associated hospitalization (2.9 hospitalizations per 1000 rifampin-pyrazinamide therapy initiations; 95% CI, 0.1-18.4) and no deaths. Articles on the use of isoniazid therapy for latent tuberculosis infection that were published after 1990 reported fatality rates of 0.0-0.3 deaths per 1000 persons. Rates of liver injury, hospitalization, and death associated with rifampin-pyrazinamide therapy exceed rates reported for isoniazid therapy. Because earlier randomized trials of rifampin-pyrazinamide lacked adequate statistical power to detect fatal events, the Centers for Disease Control and Prevention recommends that rifampin-pyrazinamide generally should not be used for treatment of latent tuberculosis infection.
    Clinical Infectious Diseases 11/2005; 41(8):1125-33. · 9.37 Impact Factor
  • Kashef Ijaz, Peter D McElroy, Thomas R Navin
    Clinical Infectious Diseases 08/2004; 39(2):289. · 9.37 Impact Factor
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    ABSTRACT: The N and W-Beijing families of Mycobacterium tuberculosis are phylogenetically closely related. The ability of the W-Beijing family to rapidly cause widespread disease is well described; however, few outbreaks involving the N family have been reported outside the New York City, N.Y., area. During 2002 to 2003, Seattle, Wash., experienced a rapidly expanding tuberculosis outbreak involving 38 persons in a 23-month period. The outbreak strain, SBRI9, exhibited the genotypic properties of the N family. Its IS6110 restriction fragment length polymorphism pattern was identical or nearly identical to those of two N family strains that were responsible for clusters of tuberculosis cases, including a large nosocomial outbreak, in New York City and New Jersey from 1989 to 1990. It was also identical to strains involved in late 1990s tuberculosis cases in Michigan, Maryland, and Arkansas. Further monitoring of the N family may show that it shares with the W-Beijing family the propensity to spread rapidly, suggesting that this characteristic evolved prior to the divergence of the two genetic lineages.
    Journal of Clinical Microbiology 04/2004; 42(3):1064-8. · 4.07 Impact Factor
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    ABSTRACT: Literature review for the process of contact tracing for sexually transmitted diseases (STD) and for tuberculosis (TB), focusing on articles that report results of studies or commentary. To compare and contrast contact tracing in order to highlight emerging commonalities. A descriptive review, based on Medline search with augmentation from other published and unpublished sources. Contact tracing for STD and TB have some obvious differences because of differing routes of transmission, differing sensibilities required to work with the affected populations, a different potential for anonymous contacts, and a major difference in the epidemiologic value of biomarkers. Nonetheless, the convergence of these processes on disadvantaged populations where drug use and sexual activity are important social factors has engendered an increasing similarity. A broadened approach to both, with greater attention to how ancillary contacts and associates may be of use in interrupting deeply embedded endemic disease transmission, deserves further study. Some newer approaches in the use of network-informed methods to elicit contacts and investigate the community dynamics of transmission may be of particular value in TB case investigation. These strategies will be enhanced by the availability of DNA fingerprinting, a powerful biomarker of recent Mycobacterium tuberculosis transmission and case association (a technology not available for STD contact tracing).
    The International Journal of Tuberculosis and Lung Disease 01/2004; 7(12 Suppl 3):S342-8. · 2.76 Impact Factor

Publication Stats

362 Citations
153.75 Total Impact Points

Institutions

  • 2008
    • Imperial College London
      • Department of Infectious Disease Epidemiology
      London, ENG, United Kingdom
  • 2007
    • University of British Columbia - Vancouver
      • Department of Medicine
      Vancouver, British Columbia, Canada
  • 2002–2007
    • Centers for Disease Control and Prevention
      • Division of Tuberculosis Elimination
      Druid Hills, GA, United States