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Chris Beyrer

Publications and source records attributed to Chris Beyrer.

At least 19 recordsLinked to original sources
PubMed2006

Novel approach for differential diagnosis of HIV infections in the face of vaccine-generated antibodies: utility for detection of diverse HIV-1 subtypes.

Because increasing numbers of HIV vaccine candidates are being tested globally, it is essential to differentiate vaccine- from virus-induced antibodies. Most of the currently tested vaccines contain multiple viral components. As a result, many vaccine recipients give positive results in FDA-licensed HIV serodetection tests. We have identified conserved sequences in Env-gp41 and Gag-p6, which are recognized soon after infection but are not included in most HIV vaccine candidates. A new HIV serodetection assay, the HIV-SELECTEST, was established that distinguishes between vaccine-induced antibodies and seroconversion due to true HIV infections. It is important to make this assay globally relevant, because many clinical trials are conducted around the world where most HIV infections are due to non-B subtype HIV-1. Therefore, the current study examined the reactivity of plasma samples from >3,000 infections with diverse HIV subtypes worldwide. The HIV-SELECTEST performed at >99% specificity and sensitivity. Both recent and established infections with clades A, B, C, D, E, F, G, J, and CRFs were detected. Antibodies elicited by other vaccinations or infections endemic to the clinical trial sites did not react in this assay. Therefore, HIV-SELECTEST could be an important differential diagnostic tool for HIV vaccine trials, blood banks, and population screening worldwide.

AIDS Serodiagnosis↗
PubMed2006

HIV voluntary counseling and testing and HIV incidence in male injecting drug users in northern Thailand: evidence of an urgent need for HIV prevention.

HIV voluntary counseling and testing (VCT), an important strategy for HIV prevention and care, has been available in all government hospitals in Thailand since 1992. We assessed factors associated with HIV testing, its uptake, and estimates of HIV incidence after HIV testing among male northern Thai injecting drug users (IDUs) admitted for inpatient drug treatment. Participants were interviewed about risk behaviors and HIV testing history before VCT was provided as part of the study. Of 825 IDUs who participated, 36% reported a prior HIV test. Factors associated with prior HIV testing in multiple logistic regression analysis included higher education and having >1 lifetime sex partner. Needle sharing was not associated with prior HIV testing. Of the 298 men with a prior test, 80% reported a negative result on their last prior HIV test, of whom 28% tested positive in our study, leading to an estimated incidence rate of 10.2 per 100 person-years. Fifty-nine percent of the IDUs who reported a prior HIV test stated that they did not receive pre- and/or posttest counseling. HIV incidence among IDUs remains high despite having VCT. Extending HIV prevention and harm reduction programs is urgently needed for IDUs in the region.

AIDS Serodiagnosis↗
PubMed2006

Marked ethnic differences in HIV prevalence and risk behaviors among injection drug users in Dushanbe, Tajikistan, 2004.

OBJECTIVE: To examine differences by ethnicity of HIV prevalence and correlates among injection drug users (IDUs) in Dushanbe, Tajikistan. METHODS: The researchers enrolled 489 active adult IDUs in a cross-sectional risk factor study of HIV infection. Participants were provided HIV pre-and posttest counseling and risk reduction counseling and answered an interviewer-administered questionnaire. HIV-1 status was determined with rapid tests and confirmed with ELISA. RESULTS: Participants included four ethnicities: 204 Tajiks (49.1%), 145 Russians (29.7%), 58 Uzbeks (11.9%), and 46 participants of other nationalities (9.4%). Overall prevalence of HIV-1 infection was 12% and varied significantly by ethnicity: it was highest among ethnic Tajiks, at 19.2%; lowest among Russians and Uzbeks, at 3.4%; and 13% among other nationalities. Ethnic groups differed significantly in years injecting, receiving a needle from a needle exchange program (NEP), injecting in groups, having undergone drug treatment, reported condom use, and arrest history. Among Tajiks, HIV infection was significantly associated with daily injecting (OR 2.16); reporting that narcotics were very easy to obtain (OR 2.46); having undergone drug treatment (OR 2.75), and injecting "alone" (OR 3.12). CONCLUSIONS: Ethnic differences were strongly associated with HIV prevalence and risk behaviors in this multiethnic study, and prevention efforts might need to be targeted by ethnicity.

Adult↗
PubMed2006

Mortality rates in conflict zones in Karen, Karenni, and Mon states in eastern Burma.

OBJECTIVES: To estimate mortality rates for populations living in civil war zones in Karen, Karenni, and Mon states of eastern Burma. METHODS: Indigenous mobile health workers providing care in conflict zones in Karen, Karenni, and Mon areas of eastern Burma conducted cluster sample surveys interviewing heads of households during 3-month time periods in 2002 and 2003 to collect demographic and mortality data. RESULTS: In 2002 health workers completed 1290 household surveys comprising 7496 individuals. In 2003, 1609 households with 9083 members were surveyed. Estimates of vital statistics were as follows: infant mortality rate: 135 (95% CI: 96-181) and 122 (95% CI: 70-175) per 1000 live births; under-five mortality rate: 291 (95% CI: 238-348) and 276 (95% CI: 190-361) per 1000 live births; crude mortality rate: 25 (95% CI: 21-29) and 21 (95% CI: 15-27) per 1000 persons per year. CONCLUSIONS: Populations living in conflict zones in eastern Burma experience high mortality rates. The use of indigenous mobile health workers provides one means of measuring health status among populations that would normally be inaccessible due to ongoing conflict.

Adolescent↗
PubMed2005

High HIV, hepatitis C and sexual risks among drug-using men who have sex with men in northern Thailand.

BACKGROUND: Men who have sex with men (MSM) and who use drugs have shown high HIV risks in Europe, and the Americas. We investigated MSM-drug user demographics, HIV sexual and drug use risks and behaviors in Chiang Mai, northern Thailand to identify prevention targets. METHODS: A total of 2005 males aged 13 years and older were enrolled during inpatient drug treatment from 1999-2000 and assessed for HIV, hepatitis C virus (HCV), syphilis, and for demographics and risks by questionnaire. Data were analyzed using chi and multiple logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Of 2005 males in treatment, 1752 (87.4%) had ever had sex, and 66 of 1752 (3.8%) reported ever having sex with another man; mostly Katoey (transgendered male) partners. MSM had higher HIV rates (OR, 2.32; 95% CI, 1.36-3.96) and were younger (P = 0.002); more likely to be Thai (P < 0.0001); better educated (P < 0.0001); had more lifetime sex partners (P < 0.0001), more female partners (P = 0.002), more female paid partners (P < 0.0001), and been paid for sex (P < 0.0001). MSM were more likely to have ever injected (P < 0.0001), sold drugs, been in prison, injected in prison, used heroin, and to have HCV (OR, 2.59; 95% CI, 1.55-4.34). CONCLUSIONS: Northern Thai MSM-drug users are at high HIV and HCV risk. In addition to sex risks with men, they have more sex with women and sex workers than other men, which fits Thai MSM patterns but not Western ones. Prevention must take into account their high rates of substance use and multiple partner types.

Adolescent↗
PubMed2005

Correlates of HIV vaccine trial participation: an Indian perspective.

Successful conduct of HIV vaccine trials in a population of great cultural diversity like India could be a challenge. Concerns, knowledge gaps and willingness to participate in future HIV vaccine trials were studied among 349 patients attending three sexually transmitted infections clinics and one reproductive tract infections clinic. Overall willingness to volunteer for HIV vaccine trials was 48%. Women and men at risk of HIV infection were willing to participate in the HIV vaccine trials. Factors associated with increased willingness to participate in these trials were awareness of current HIV vaccine efforts, realization of importance of vaccine for self, concern about adverse events and altruism.

AIDS Vaccines↗
PubMed2005

Personal history of voluntary HIV counseling and testing (VCT) among adults aged 19-35 years living in peri-urban communities, Chiang Mai, Northern Thailand.

This study investigates the self-reported history of HIV voluntary counseling and testing (VCT) among adults, aged 19-35 years, in northern Thailand. Participants were interviewed about their HIV testing history and risk behavior. Overall, 47% of 2251 participants had previously been tested, of whom 64% were tested at government clinics. Of those tested at private clinics, 50% reported not receiving pre- and post-test counseling, compared to 15% of those tested in government clinics. Ten percent of those tested had not received their test results. Among those who had never been previously tested for HIV, 66% believed they were not at risk, although 1.5% (2.7% among men) were HIV infected. Although VCT is widely available and utilized by the population of northern Thailand, substantial numbers of HIV infected persons have not been tested for HIV and among those tested many have not received comprehensive counseling. A Thai government policy enforcing effective counseling to accompany HIV testing is urgently needed.

AIDS Serodiagnosis↗
PubMed2005

Changes in willingness to participate in HIV vaccine trials among HIV-negative injection drug users.

Injection drug users (IDUs) represent an important risk group for HIV infection. We assessed correlates of IDUs' willingness to participate (WTP) in HIV vaccine trials, and examined temporal changes in WTP. Participants were enrolled in ALIVE, a prospective study of HIV among IDUs in Baltimore; semi-annual visits include interviews and HIV serology. Questionnaires regarding WTP were administered in 1993-1994 and again in 2001-2002. Logistic regression was conducted to identify correlates of WTP. Wave 1 of the survey included 440 participants; Wave 2 included 582 participants (189 participated in both waves). WTP increased modestly over time (83.4 vs. 86.3%; p = 0.16). Monetary incentives were the strongest predictor of WTP (adjOR = 2.73; 95% CI: 1.72-4.35). High expectations of HIV treatment effectiveness did not predict WTP. In this cohort, WTP remained strong and modestly increased over the study period. These results should be considered in the planning of sampling and retention strategies for future vaccine trials.

AIDS Serodiagnosis↗
PubMed2004

HIV infection among female drug users in Northern Thailand.

Reports on HIV infection and risk behaviors among female drug users in developing countries, particularly in Asia, are limited. In this study, we investigated HIV prevalence and risk factors for HIV infection among 200 women admitted for 21-day inpatient drug detoxification in Chiang Mai, Thailand. Volunteers completed a face-to-face interview using a structured interview, HIV pre-test counseling, specimen collection for HIV and STD tests, and were provided test results and HIV post-test counseling 1 week later. Two-third of participants (68%) were ethnic minorities with no formal education. Overall, 14 (7%) were HIV positive: 25% among 28 heroin injectors and 4.1% among 172 opium or methamphetamine smokers (p<0.001). History of drug injection and sexual abuse were associated with HIV infection. HIV prevention strategies for drug-using women in Thailand should consider both harm reduction strategies for drug use and promoting safer sex measures in a culturally appropriate context.

Adult↗
PubMed2004

The natural history of HIV-1 infection in young Thai men after seroconversion.

The natural history and progression of HIV-1 infection in Thailand and other developing countries in Asia and Africa have not been well defined. Nevertheless, valid data are needed to evaluate the effects of interventions, which are designed to delay progression. We evaluated the progression to AIDS and death in 235 men who seroconverted during their 2 years of service in the Royal Thai Army. The men were conscripted at age 21 and seroconverted within a 6-month window during follow-up while in the military. The seroconverters were matched with men who were seronegative when discharged. Of the HIV-positive men, 156 (66.4%) were alive, 77 (32.8%) had died, and 2 (0.8%) could not be located 5-7 years after their seroconversion and discharge from the military. The 5-year survival rate was 82.3%; the median times to clinical AIDS and a CD4 cell count of <200/microL was 7.4 years and 6.9 years, respectively. The mortality rate was 56.3 deaths per 1000 patient-years for HIV-positive men and 6.1 deaths per 1000 patient-years for HIV-negative men. Our data suggest a more rapid progression to AIDS and death after HIV-1 infection in young men in Thailand than has been reported for similarly aged cohorts in developed countries.

Acquired Immunodeficiency Syndrome↗
PubMed2004

The changing molecular epidemiology of HIV type 1 among northern Thai drug users, 1999 to 2002.

CRF01_AE and subtype B have dominated the HIV-1 epidemic in Thailand since 1989. We reported a new circulating recombinant form of HIV-1, CRF15_01B, as well as other unique CRF01_AE/B recombinants among prevalent HIV infections in Thailand. We sought to study this challenging molecular picture through assessment of subtypes among recent HIV-1 seroconverters in northern Thai drug users. A total of 847 HIV-1 seronegative drug users (342 IDU and 505 non-IDU) were enrolled, from 1999 to 2002, in a prospective study; 39 HIV-1 incident cases were identified and characteristics were collected. The overall HIV-1 incidence rate was 2.54/100PY, but it was 10.0/100PY among male IDU. HIV was strongly associated with injection history; 38 of 39 seroconverters gave a history of IDU. A near full-length genome of HIV-1 was recovered by PCR amplification and sequenced from peripheral mononuclear cell extracted DNA of 38 seroconverters. Phylogenetic analysis revealed that 33 (86.8%) were CRF01_AE and 5 (13.2%) were CRF01_AE/B recombinants. These recombinants had different structure but shared some common breakpoints, indicating an ongoing recombination process. Recombinant infection increased with year of sampling (0 to 57.1%). The molecular epidemiology of HIV-1 among drug users in northern Thailand has thus entered a new era. CRF01_AE remains predominant while pure subtype B is becoming rare, and now a substantial component of the epidemic. These findings support the need for CRF01_AE and subtype B components in clade-matched vaccine strategies for Thai phase III trials. Ongoing molecular surveillance of circulating HIV-1 strains is imperative for the evaluation of HIV vaccine efficacy.

Base Sequence↗
PubMed2003

HIV prevalence and risks among injection and noninjection drug users in northern Thailand: need for comprehensive HIV prevention programs.

The authors sought to determine sociodemographic and sexual and drug use risk factors for HIV infection among drug users in northern Thailand adjacent to the Golden Triangle. The authors enrolled patients admitted for inpatient drug detoxification at one treatment center in northern Thailand and studied HIV risks and prevalence using an interviewer-administered questionnaire and serum collection with HIV pretest and posttest counseling. Between February 1, 1999 and January 31, 2000, 1865 patients admitted for opiate and methamphetamine dependence completed study procedures. Overall HIV prevalence was 10.3%: 30.0% among 513 injection drug users (IDUs) and 2.8% among non-IDUs (OR = 14.8, 95% CI: 10.2, 21.6). HIV seroprevalence was 2.4% among exclusive methamphetamine users (98% of whom are non-IDUs) and 3.4% among opium smokers. Injection drug use was the dominant risk factor in multivariate models. Although Thailand is widely recognized as having a successful national response to the heterosexual HIV epidemic, seroprevalence in IDUs remains high. Despite a sharp increase of non-IDUs admitted to the drug treatment center, HIV infection and risks remained high among IDUs in northern Thailand. HIV prevention campaigns need to focus on IDUs and to implement harm reduction strategies to reduce transmission to IDUs and further contain the HIV epidemic in Thailand.

Adolescent↗
PubMed2003

Assessing the magnitude of the HIV/AIDS epidemic in Burma.

OBJECTIVES: Estimates of the HIV/AIDS burden in Burma (Myanmar) are uncertain. Using data from the 1999 national HIV sentinel surveillance and available population data, we generated estimates of Burma's HIV burden in 1999. METHODOLOGY: The 1999 sentinel surveillance included women attending antenatal clinics, male military recruits, blood donors, injecting drug users, patients of sexually transmitted disease clinics, and sex workers. We used data for women attending antenatal clinics and male recruits aged 20-29 years to estimate HIV prevalence among women and men, respectively. Data points were merged to give five regional estimates of prevalence for men and women. Census figures were used to obtain national population estimates of the numbers of Burmese living with HIV infection, along with confidence intervals (CIs). RESULTS: HIV prevalence varied by region, with the lowest rates in the West, intermediate rates in the central region, and highest rates in the North, East, and South. The highest rates were in the East (Shan State), with female prevalence of 3.0% (95% CI, 1.9-4.5). The total number of infected women nationwide was 218,300 (95% CI, 159,400-277,100), and that of men was 468,700 (95% CI, 343,300-594,200). We estimated HIV prevalence of at least 3.46% (95% CI, 2.72-4.19) among adults aged 15-44 years; 5700 infants were born with HIV infection in 1999. DISCUSSION: Burma has a generalized epidemic of HIV-1 in reproductive age adults. We estimated that there were 687,000 (95% CI, 541,100-832,900) Burmese adults living with HIV infection in 1999, or about one of every 29 adult citizens. This estimate is higher than the UNAIDS estimate for the same year of 530,000 adults and children living with AIDS, or a population prevalence of about one in 50 adults. HIV prevention and care programs are urgently needed in Burma.

Acquired Immunodeficiency Syndrome↗