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Biomedical subjects

B A Koblin

Publications and source records attributed to B A Koblin.

At least 19 recordsLinked to original sources
PubMed2006

Violence and HIV-related risk among young men who have sex with men.

Limited research has been conducted on threats or violence by family members and sexual partners against young men who have sex with men (MSM). Young MSM, aged 15-22 years, who attended public venues in New York City were enrolled in an anonymous, cross-sectional HIV seroprevalence and risk-behavior study. About two-thirds (68%) of the young MSM reported ever experiencing threats or violence from either family or partners and 25% reported threats or violence by both family and partners. In multivariate analysis, threats or violence by partners was significantly associated with older age, a history of forced sex and a history of running away from home. Recent unprotected anal sex and club drug use were significantly associated with a history of threats or violence by both family and partners. HIV prevention interventions need to include multiple factors that may have an impact on risk, including substance use and abuse, anti-violence and other mental-health issues.

Adolescent↗
PubMed2001

Are US populations appropriate for trials of human immunodeficiency virus vaccine? The HIVNET Vaccine Preparedness Study.

Questions exist about whether testing of preventive human immunodeficiency virus (HIV)-1 vaccines, which will require rapid recruitment and retention of cohorts with high HIV-1 seroincidence, is feasible in the United States. A prospective cohort study was conducted in 1995-1997 among 4,892 persons at high risk for HIV infection in nine US cities. At 18 months, with an 88% retention rate, 90 incident HIV-1 infections were observed (1.31/100 person-years (PY), 95% confidence interval (CI): 1.06, 1.61). HIV-1 seroincidence rates varied significantly by baseline eligibility criteria--1.55/100 PY among men who had sex with men, 0.38/100 PY among male intravenous drug users, 1.24/100 PY among female intravenous drug users, and 1.13/100 PY among women at heterosexual risk-and by enrollment site, from 0.48/100 PY to 2.18/100 PY. HIV-1 incidence was highest among those men who had sex with men who reported unprotected anal intercourse (2.01/100 PY, 95% CI: 1.54, 2.63), participants who were definitely willing to enroll in an HIV vaccine trial (1.96/100 PY, 95% CI: 1.41, 2.73), and women who used crack cocaine (1.62/100 PY, 95% CI: 0.92, 2.85). Therefore, cohorts with HIV-1 seroincidence rates appropriate for HIV-1 vaccine trials can be recruited, enrolled, and retained.

AIDS Vaccines↗
PubMed2001

Two decades after vaccine license: hepatitis B immunization and infection among young men who have sex with men.

OBJECTIVES: This study investigated hepatitis B immunization coverage and the extent of hepatitis B virus (HBV) infection among young men who have sex with men (MSM), a group for whom hepatitis B vaccine has been recommended since 1982. METHODS: We analyzed data from 3432 MSM, aged 15 to 22 years, randomly sampled at 194 gay-identified venues in 7 US metropolitan areas from 1994 through 1998. Participants were interviewed, counseled, and tested for serologic markers of HBV infection. RESULTS: Immunization coverage was 9% and the prevalence of markers of HBV infection was 11%. HBV infection ranged from 2% among 15-year-olds to 17% among 22-year-olds. Among participants susceptible to HBV infection, 96% used a regular source of health care or accessed the health care system for HIV or sexually transmitted disease testing. CONCLUSIONS: Despite the availability of an effective vaccine for nearly 2 decades, our findings suggest that few adolescent and young adult MSM in the United States are vaccinated against hepatitis B. Health care providers should intensify their efforts to identify and vaccinate young MSM who are susceptible to HBV.

Adolescent↗
PubMed2001

Retaining hard-to-reach women in HIV prevention and vaccine trials: Project ACHIEVE.

Project ACHIEVE, which conducts HIV prevention research studies, maintains a women's site in the South Bronx in NewYork City. Owing to a focused retention effort at the South Bronx site, high retention rates were achieved in a vaccine preparedness study for women at high risk of HIV infection. Comparable retention rates have been achieved in HIV vaccine trials with similar cohorts of women at this site. These results suggest that concerns about retaining hard-to-reach populations should not cause these populations to be excluded from HIV vaccine and prevention trials.

AIDS Serodiagnosis↗
PubMed2000

High prevalence of HIV infection among young men who have sex with men in New York City.

OBJECTIVE: To determine the prevalence of HIV infection and risk behaviors among young men who have sex with men (MSM) aged 15-22 years in New York City. DESIGN: An anonymous cross-sectional survey. METHODS: The 1998 Young Men's Survey in New York City (YMS-NYC), was a multistage probability survey of 541 MSM aged 15-22 years who attend public venues. After identification of venues and their associated high attendance time periods, random samples of venues and time periods were selected on a monthly basis. At each sampling event, potential participants were approached to determine eligibility. Eligible and willing men were interviewed, counselled and had a blood specimen drawn. RESULTS: Between December 1997 and September 1998, 115 sampling events were conducted. Of 612 men enrolled, 541 reported ever having had sex with a male partner. The HIV seroprevalence among the 541 MSM sampled was 12.1%. The HIV seroprevalence was 18.4% among African-Americans, 16.7% among persons of mixed race, 8.8% among Latino individuals and 3.1% among white men. HIV seroprevalence was 5.0% among 15-18 year olds and 16.4% among 19-22 year olds. A total of 65.5% of MSM were susceptible to hepatitis B virus infection (HBV). Almost half (46.1%) of the men reported unprotected anal sex in the previous 6 months and 16.3% reported ever having had an STD. Multiple regression analyses found that being older, of mixed race, black or ever having had an STD was associated with being HIV antibody positive. CONCLUSION: These data identify a large subgroup of MSM in need of effective HIV and HBV primary and secondary prevention programs.

AIDS Serodiagnosis↗
PubMed2000

Readiness for HIV vaccine trials: changes in willingness and knowledge among high-risk populations in the HIV network for prevention trials. The HIVNET Vaccine Preparedness Study Protocol Team.

Longitudinal data were analyzed to determine changes in willingness to participate in HIV vaccine efficacy trials and knowledge of vaccine trial concepts among populations at high risk of HIV-1 infection. Gay men (MSM), male and female injection drug users, and non-injecting women at heterosexual risk were recruited (n = 4892). Follow-up visits occurred every 6 months up to 18 months. Willingness was significantly lower at follow-up visits compared with at baseline. Knowledge levels increased for all study populations. Problematic concepts were possible effects of the vaccine on the immune system and lack of knowledge about efficacy of a vaccine before the start of a trial. For concepts concerning safety, blinding, and guarantees of future participation in trials, MSM men had significant increases in knowledge, but little to no change occurred for the other populations. An increase in knowledge was associated with becoming not willing, particularly among MSM with low knowledge levels. At least half of high-risk participants were consistently willing to participate in future vaccine efficacy trials and with basic vaccine education, knowledge levels increased. Continued educational efforts at the community and individual level are needed to address certain vaccine trial concepts and to increase knowledge levels in all potential study populations.

AIDS Vaccines↗
PubMed2000

Anal sex among HIV-seronegative women at high risk of HIV exposure. The HIVNET Vaccine Preparedness Study 2 Protocol Team.

To assess the prevalence and the sociodemographic and behavioral correlates of anal sex in a cohort of HIV-seronegative U.S. women at high risk of HIV exposure, we administered a risk assessment using audio computer-assisted self-interview (A-CASI). Of 1268 sexually active women, 432 (32%) reported anal sex in the previous 6 months. Compared with women who did not report anal sex, those who did had more unprotected vaginal sex (median of 11 versus 7 episodes; p <. 001) and a higher proportion of unprotected sexual (vaginal plus anal) episodes (median of 0.90 versus 0.81; p =.01). Anal sex was reported by higher proportions of women who did not always use condoms, who used crack in the past year, who were </=35 years of age, with no formal education beyond high school, who had had a diagnosed sexually transmitted disease in the previous year, a primary male sex partner, and a male sex partner with a history of injecting use. Women were more likely to report anal sex by A-CASI than during interviewer-administered risk assessments (odds ratio [OR], 9.00; 95% confidence interval [CI], 1.14-71.0). A less biased method of ascertainment may account for the large proportion of women reporting anal sex. Given increased vaginal risk among women reporting anal sex, the relative importance of anal sex in heterosexual transmission merits further study. Behavioral and biomedical prevention strategies effective for anal as well as vaginal sex are needed.

Adolescent↗
PubMed2000

HIV prevalence and associated risks in young men who have sex with men. Young Men's Survey Study Group.

CONTEXT: Studies conducted in the late 1980s on human immunodeficiency virus (HIV) infection among older men who have sex with men (MSM) suggested the epidemic had peaked; however, more recent studies in younger MSM have suggested continued high HIV incidence. OBJECTIVE: To investigate the current state of the HIV epidemic among adolescent and young adult MSM in the United States by assessing the prevalence of HIV infection and associated risks in this population in metropolitan areas. DESIGN: The Young Men's Survey, a cross-sectional, multisite, venue-based survey conducted from 1994 through 1998. SETTING: One hundred ninety-four public venues frequented by young MSM in Baltimore, Md; Dallas, Tex; Los Angeles, Calif; Miami, Fla; New York, NY; the San Francisco (Calif) Bay Area; and Seattle, Wash. SUBJECTS: A total of 3492 15- to 22-year-old MSM who consented to an interview and HIV testing. MAIN OUTCOME MEASURES: Prevalence of HIV infection and associated characteristics and risk behaviors. RESULTS: Prevalence of HIV infection was high (overall, 7.2%; range for the 7 areas, 2.2%-12. 1%) and increased with age, from 0% among 15-year-olds to 9.7% among 22-year-olds. Multivariate-adjusted HIV infection prevalence was higher among blacks (odds ratio [OR], 6.3; 95% confidence interval [CI], 4.1-9.8), young men of mixed or other race (OR, 4.8; 95% CI, 3. 0-7.6), and Hispanics (OR, 2.3; 95% CI, 1.5-3.4), compared with whites (referent) and Asian Americans and Pacific Islanders (OR, 1. 1; 95% CI, 0.5-2.8). Factors most strongly associated with HIV infection were being black, mixed, or other race; having ever had anal sex with a man (OR, 5.0; 95% CI, 1.8-13.8); or having had sex with 20 or more men (OR, 3.0; 95% CI, 2.0-4.7). Only 46 (18%) of the 249 HIV-positive men knew they were infected before this testing; 37 (15%) were receiving medical care for HIV, and 19 (8%) were receiving medical drug therapy for HIV. Prevalence of unprotected anal sex during the past 6 months was high (overall, 41%; range, 33%-49%). CONCLUSIONS: Among these young MSM, HIV prevalence was high, underscoring the need to evaluate and intensify prevention efforts for young MSM, particularly blacks, men of mixed race or ethnicity, Hispanics, and adolescents. JAMA. 2000;284:198-204

AIDS Serodiagnosis↗
PubMed2000

Involving women in HIV vaccine efficacy trials: lessons learned from a vaccine preparedness study in New York City.

This paper identifies the recruitment strategies and human immunodeficiency virus (HIV) risk behaviors of at-risk women in an HIV vaccine preparedness study in New York City, assesses how these behaviors changed over time, and draws implications for women's involvement in HIV vaccine efficacy trials. Noninjecting HIV-1 negative women (N = 89) were recruited into an HIV vaccine preparedness study. An observational cohort study design was used. Women were recruited from clinics and community-based organizations (40%), through other study participants (24%), through newspaper advertisements (20%), and through street outreach (16%). Most women who refused (72%) also came from clinics and agencies. Retention after 12 months was 67%; after 18 months, it was 62%. The proportion of women reporting unprotected vaginal sex in the previous 3 months was 85% at baseline and declined to 70% after 12 months (P < .05). There have been no seroconversions detected. Recruitment efforts to include at-risk women in HIV vaccine efficacy trials must be diverse and actively involve community agencies. Successfully retaining these cohorts over time and detecting a high enough HIV seroincidence rate present ongoing challenges that will need to be addressed to ensure women's involvement in future trials in the US.

AIDS Vaccines↗
PubMed2000

Acceptability of a stage-matched expert system intervention to increase condom use among women at high risk of HIV infection in New York City.

There is an urgent need to develop and implement effective methods for sexual behavior change to curb the spread of HIV. Condoms remain one of the most effective strategies for achieving this, yet consistent condom use is generally low, especially among those at highest risk. This article describes the acceptability of an interactive computer-based expert system designed to increase condom use in women at high risk of HIV infection. The expert system is based on the transtheoretical stages of change model. Using a computer, participants respond to questions about their attitudes and behavior toward using condoms and receive immediate feedback which is matched to their readiness to use condoms. The women were found to be at all stages of change for condom use, although a large proportion of the women (42%) were at early stages of behavior change because they were considering but not using condoms every time during sex with men. The expert system was found to be acceptable to this high-risk group of women. They almost unanimously agreed that they found the feedback useful, would return to use the system again, and would recommend it to a friend. These findings indicate that traditional intervention strategies which assume individuals are ready to use condoms consistently would be appropriate for only about one third of these women, underscoring the importance and potential utility of stage-matched interventions.

Adolescent↗
PubMed1999

Long-term survival after infection with human immunodeficiency virus type 1 (HIV-1) among homosexual men in hepatitis B vaccine trial cohorts in Amsterdam, New York City, and San Francisco, 1978-1995.

Information on long-term survival after infection with human immunodeficiency virus type 1 (HIV-1) is limited. In hepatitis B vaccine trials in Amsterdam, New York City, and San Francisco, 362 gay men were followed up to 18 years (1978-1995). The median survival time from seroconversion was 12.1 years (95% confidence interval: 11.4, 12.9). The annual risk of dying increased at a constant rate until 8 years after seroconversion and then leveled off, suggesting a group that is relatively resistant to progression. These data provide a picture of the natural history of HIV-1 infection, especially in the era prior to widespread use of highly effective treatments.

Adult↗
PubMed1999

Correlates of condom failure in a sexually active cohort of men who have sex with men.

Condom failure (slippage or breakage) has been shown to be associated with HIV seroconversion among men who have sex with men (MSM), but predictors of failure have been poorly elucidated. Of 2592 HIV-seronegative MSM participants in the HIV Network for Prevention Trials (HIVNET) multisite Vaccine Preparedness Study who reported condom use for anal sex in the 6 months before enrollment, condom failure was reported by 16.6%, with failure rates of 2.1/100 episodes of condom usage (2.5 failures/100 episodes for receptive anal sex and 1.9/100 episodes for insertive anal sex). In separate multivariate models evaluating predictors of condom failure reported by the insertive and receptive partners, more frequent condom use was associated with a decreased per-condom failure rate and amphetamine and heavy alcohol use with increased rates in both models. Being employed, having private medical insurance, and using lubricants for >80% of anal sex acts were significantly associated with decreased failure rates in the insertive model. Safer sex counseling should particularly target men of lower socioeconomic status, promote proper and consistent use of condoms with appropriate lubricants, and address the impact of drug use, especially amphetamines and alcohol, on condom failure.

Adult↗
PubMed1999

Non-injection substance use correlates with risky sex among men having sex with men: data from HIVNET.

Associations between substance use and sexual behavior were examined among 3220 seronegative men who have sex with men (MSM) in a HIV vaccine preparedness study. Relationships between current and past substance use and current sexual risk were evaluated using crude odds ratios and logistic regression to adjust for confounding variables. Heroin and injection drug use were uncommon (< 2%). Substances most often used were alcohol (89%), marijuana (49%), nitrite inhalants (29%), amphetamines or similarly acting stimulants (21%), cocaine 14% and hallucinogens (14%). Increased adjusted odds for unprotected sex were significantly associated with current heavy alcohol use (OR 1.66; CI 1.18, 2.33), past alcohol problems (OR 1.25; CI 1.05, 1.48), and current drug use (OR 1.26; CI 1.08, 1.48). When associations with specific drugs and nitrite inhalants were examined separately, current use of cocaine and other stimulants (OR 1.25; CI 1.01, 1.55), hallucinogens (OR 1.40; CI 1.10, 1.77), and nitrite inhalants (some (OR 1.61; CI 1.35, 1.92); heavy (OR 2.18; CI 1.48, 3.20)), were independently associated with unprotected sex. Those with past drug use or past heavy alcohol use but not currently using demonstrated no increase in sexual risk, suggesting an important role for substance-focused interventions in risk reduction efforts among MSM.

AIDS Vaccines↗
PubMed1999

Use of reality "female condoms" for anal sex by US men who have sex with men. HIVNET Vaccine Preparedness Study Protocol Team.

OBJECTIVES: This study assessed use of Reality "female condoms" for anal sex by HIV-seronegative men who have sex with men and are at high risk for HIV infection. METHODS: Self-administered questionnaires were completed by 2277 participants in a 6-city prospective cohort study. RESULTS: Of the 1084 (48%) men who had heard of using the female condom for anal sex, 145 (13%) reported using it in the prior 6 months. Users were at greater risk than nonusers: 47 receptive and 35 insertive users reported problems, including bleeding by the receptive partner (4). CONCLUSIONS: Redesign of the female condom could increase acceptability and use by men who have sex with men and could address possible safety concerns.

Adult↗
PubMed1998

Readiness of high-risk populations in the HIV Network for Prevention Trials to participate in HIV vaccine efficacy trials in the United States.

OBJECTIVE: To determine the willingness of populations at high risk of HIV-1 infection to participate in HIV vaccine efficacy trials, determine factors influencing decision-making, and evaluate knowledge levels of vaccine trial concepts. DESIGN: Cross-sectional study. METHODS: HIV-1-negative homosexual men, male and female injecting drug users and non-injecting women at heterosexual risk were recruited in eight cities in the United States (n=4892). RESULTS: A substantial proportion of the study population (77%) would definitely (27%) or probably (50%) be willing to participate in a randomized vaccine efficacy trial. Increased willingness was associated with high-risk behaviors, lower education level, being uninsured or covered by public insurance, and not having been in a previous vaccine preparedness study. Altruism and a desire for protection from the vaccine were major motivators for participation. Major concerns included positive HIV-1 antibody test due to vaccine, safety of the vaccine, and possible problems with insurance or foreign travel. Baseline knowledge of vaccine trial concepts was low. CONCLUSIONS: It is likely that high-risk volunteers will be willing to enroll in HIV vaccine efficacy trials. A variety of participant and community educational strategies are needed to address participant concerns, and to ensure understanding of key concepts prior to giving consent for participation.

AIDS Vaccines↗
PubMed1997

Willingness to participate in HIV-1 vaccine efficacy trials and the effect of media events among gay and bisexual men in New York City: Project ACHIEVE.

Efficacy trials of candidate HIV-1 vaccines require study populations at high risk of infection who adhere to study protocols and who are willing to participate. Data from HIV-1 antibody-negative men (n = 698) enrolled in Project ACHIEVE in New York City were analyzed to assess willingness to participate in efficacy trials, factors influencing willingness, and the effect on willingness of the June 1994 media events about the decision not to proceed with phase III trials and about breakthrough infections during phase I and II vaccine trials. Sixty-eight percent indicated they would definitely or probably be willing to participate. Men enrolled during the time of media events were significantly less willing compared with men enrolled during other periods. These men were also more likely to mention safety of the vaccine, fear or mistrust of research or government, and social risks as important factors in their decision compared with men enrolled during other periods. The most frequently cited motivator for participation was altruism (57%); the most frequently cited barriers were vaccine safety (36%) and vaccine-induced seropositivity (19%). A substantial proportion of this cohort was willing to participate in future vaccine efficacy trials. However, because willingness may be affected by issues of vaccine safety, vaccine-induced seropositivity, and media coverage of these issues, significant efforts are needed for participant and community education, and specific concerns must be addressed in the design and implementation of trials.

Adult↗
PubMed1996

Increased incidence of cancer among homosexual men, New York City and San Francisco, 1978-1990.

Several studies have shown that human immunodeficiency virus type 1 (HIV-1) is associated with an increase in the incidence of Kaposi's sarcoma and non-Hodgkin's lymphoma among homosexual men. The role of HIV-1 in increasing the incidence of other malignancies is more controversial. The incidence of non-Kaposi's sarcoma cancer was examined from 1978 to 1990 among 15,565 homosexual men who participated in studies of hepatitis B virus infection in the late 1970s in New York City, New York, and San Francisco, California. The standardized incidence ratio (SIR) for all cancers was 1.6 (95% confidence interval (CI) 1.4-1.8). Excesses were observed for non-Hodgkin's lymphoma (SIR = 12.7; 95% CI 11.0-14.6). Hodgkin's disease (SIR = 2.5; 95% CI 1.5-3.9), and anal cancer (SIR = 24.2 95% CI 13.5-39.9). As seen with non-Hodgkin's lymphoma, a cancer known to be associated with HIV-1. Hodgkin's disease incidence was significantly higher in more recent years compared with earlier years. No cases of Hodgkin's disease were found among HIV-1 antibody-negative men, and Hodgkin's disease was diagnosed near the time of initial acquired immunodeficiency syndrome diagnoses. Anal cancer incidence did not correlate with HIV-1 antibody status and did not tend to occur near the time of AIDS diagnoses. This study confirms the association of non-Hodgkin's lymphoma with HIV-1 infect on and suggests an association between Hodgkin's disease and HIV-1 infection. An excess in anal cancer was observed but did not appear to be associated with HIV-1 infection.

Acquired Immunodeficiency Syndrome↗