Biomedical subjects

Richard J Hayes

Publications and source records attributed to Richard J Hayes.

15 recordsLinked to original sources

PubMed2005

Effect of routine isoniazid preventive therapy on tuberculosis incidence among HIV-infected men in South Africa: a novel randomized incremental recruitment study.

CONTEXT: Tuberculosis preventive therapy reduces tuberculosis incidence among human immunodeficiency virus (HIV)-infected individuals in clinical trials, but implementation has been limited and there are no data on effectiveness under routine conditions. OBJECTIVE: To determine the effect on tuberculosis incidence of a clinic providing isoniazid preventive therapy to HIV-infected adults under routine conditions. DESIGN, SETTING, AND PARTICIPANTS: Randomized intervention study with a novel incremental recruitment design. Between 1999 and 2001 (before antiretroviral therapy was available), 1655 HIV-infected male employees of a South African gold-mining company (median age, 37 years) were enrolled in the study. Median follow-up was 22.1 months. INTERVENTION: Employees were invited in random sequence to attend a workplace HIV clinic. Isoniazid, 300 mg/d, was self-administered for 6 months among attendees with no evidence of active tuberculosis. MAIN OUTCOME MEASURE: Incidence of tuberculosis (including both first and recurrent episodes) during the periods before and after clinic enrollment. RESULTS: A total of 1016 of 1655 men included in the analysis attended the clinic at least once. Six hundred seventy-nine (97%) of 702 men eligible to start primary isoniazid preventive therapy did so. The tuberculosis incidence rate before vs after clinic enrollment was 11.9 vs 9.0 per 100 person-years, respectively (incidence rate ratio [IRR] after adjustment for calendar period, 0.68; 95% confidence interval [CI], 0.48-0.96). In a multivariable analysis adjusting for calendar period, age, and silicosis grade, the tuberculosis IRR for clinic enrollment was 0.62 (95% CI, 0.43-0.89). In a further analysis excluding individuals with a history of tuberculosis (and, hence, ineligible for isoniazid preventive therapy), the adjusted IRR for clinic enrollment was 0.54 (95% CI, 0.35-0.83). CONCLUSIONS: Enrollment in a clinic offering primary isoniazid preventive therapy to HIV-infected adults reduced tuberculosis incidence by 38% overall and by 46% among individuals with no history of tuberculosis prior to the study. Tuberculosis incidence remained high despite isoniazid preventive therapy, and further work is needed to determine how to use additional interventions most effectively to reduce morbidity and mortality due to tuberculosis in HIV-infected persons.

AIDS-Related Opportunistic Infections↗

PubMed2005

The appropriateness of core group interventions using presumptive periodic treatment among rural Zimbabwean women who exchange sex for gifts or money.

To map the characteristics of rural based sex workers in Zimbabwe with regard to demographics, mobility, behavior, HIV and sexually transmitted infection (STI) prevalence, to explore the appropriateness and feasibility of presumptive periodic treatment (PPT) for bacterial STIs as an HIV prevention intervention among these women, and to compare tolerability of 2 PPT regimens (1 g of azithromycin and 2 g of metronidazole+/-500 mg of ciprofloxacin). Five commercial farms and 2 mines in Mashonaland West, Zimbabwe. Three hundred sixty-three sex workers were recruited and completed a structured interviewer-administered questionnaire. Each participant had blood tested for antibody to HIV, herpes simplex virus 2 (HSV-2), and syphilis; urine tested for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG); and a vaginal swab tested for Trichomonas vaginalis (TV). Women were randomly assigned to receive a single dose of 1 of 2 PPT regimens and then followed to assess rates of side effects and reinfection. The overall prevalence of antibody to HIV was 55.7% (95% confidence interval [CI]: 50.6-60.9) and that of HSV-2 was 80.8% (95% CI: 76.7-84.9). The prevalence of CT and NG was low (CT=1.7%, 95% CI: 0.3-3.0); (NG=1.9%, 95% CI: 0.5-3.4), with a much higher prevalence of TV (TV=19.3%, 95% CI: 15.2-23.4). Prevalence of CT, NG, and TV was appreciably reduced 1 month after PPT but rose to pretreatment levels at the 2- and 3-month visits. The rate of moderate or severe side effects after PPT was low, but it was higher in the women who received ciprofloxacin in addition to azithromycin and metronidazole (P=0.007). It was feasible to access women who reported exchanging money or gifts for sex in rural communities, although many of these women engaged in sex work only infrequently. The prevalence of bacterial STIs was low, suggesting that PPT may not be an appropriate intervention in this setting. Rapid reinfection after PPT suggests that this needs to be given at monthly intervals to reduce prevalence of STIs.

Adult↗

PubMed2005

The MEMA kwa Vijana project: design of a community randomised trial of an innovative adolescent sexual health intervention in rural Tanzania.

BACKGROUND: Effective interventions to reduce the incidence of HIV, other sexually transmitted infections (STIs) and unwanted pregnancy among adolescents in sub-Saharan Africa are urgently needed. This paper describes the rationale and design of a randomised trial of the impact of an innovative sexual health intervention among adolescents in rural Mwanza Region, Tanzania. METHODS: The MEMA kwa Vijana intervention comprises a teacher-led, peer-assisted sexual health education programme for students in the last 3 years of primary school, training and supervision of health workers in the provision of youth-friendly health services, peer condom promotion and distribution, and wider community activities. Detailed process evaluation was conducted and the impact of the intervention was evaluated through a community-randomised trial in which a cohort of 9645 adolescents was followed up for 3 years. Both process and impact evaluation used multiple assessment methods. Impact measures included incidence and prevalence of HIV and other STIs, pregnancy rates, knowledge and reported attitudes and sexual behaviour, as well as qualitative assessments. RESULTS: Results of the baseline survey of the cohort have been presented previously. The outcome of the trial will be reported separately. CONCLUSIONS: Behaviour change interventions among adolescents have been widely advocated, but there have been few rigorously designed trials of their effectiveness, particularly in developing countries, and measurement of sexual behaviour is particularly problematic in this age group. The MEMA kwa Vijana trial was undertaken to address these problems and to collect rigorous evidence on the effectiveness of an innovative intervention, designed to be implemented on a very large scale.

Adolescent↗

PubMed2004

Can population differences explain the contrasting results of the Mwanza, Rakai, and Masaka HIV/sexually transmitted disease intervention trials?: A modeling study.

OBJECTIVE: To determine whether population differences can explain the contrasting impacts on HIV observed in the Mwanza trial of sexually transmitted disease (STD) syndromic treatment (ST), the Rakai trial of STD mass treatment (MT), and the Masaka trial of information, education, and communication (IEC) with and without ST as well as to predict the effectiveness of each intervention strategy in each population. METHODS: Stochastic modeling of the transmission of HIV and 6 STDs was used with parameters fitted to demographic, sexual behavior, and epidemiological data from the trials and general review of STD/HIV biology. RESULTS: The baseline trial populations could be simulated by assuming higher risk behavior in Uganda compared with Mwanza in the 1980s, followed by reductions in risk behavior in Uganda preceding the trials. In line with trial observations, the projected HIV impacts were larger for the ST intervention in Mwanza than for the MT intervention in Rakai or the IEC and IEC + ST interventions in Masaka. All 4 simulated intervention strategies were more effective in reducing incidence of HIV infection in Mwanza than in either Rakai or Masaka. CONCLUSIONS: Population differences in sexual behavior, curable STD rates, and HIV epidemic stage can explain most of the contrast in HIV impact observed between the 3 trials. This study supports the hypothesis that STD management is an effective HIV prevention strategy in populations with a high prevalence of curable STDs, particularly in an early HIV epidemic.

Adolescent↗

PubMed2004

Does tuberculosis increase HIV load?

BACKGROUND: The effect that tuberculosis (TB) has on human immunodeficiency virus (HIV) disease progression is not clearly understood. METHODS: In an observational cohort study of HIV-infected adults in South Africa, baseline and final HIV load were compared between individuals who experienced an episode of TB (n=30) during follow-up and control subjects (n=56) matched by baseline CD4 cell count and follow-up time; linear regression modeling was used to control for confounding. RESULTS: Mean HIV load was higher in the TB group than in the non-TB control group for both baseline (4.73 vs. 4.24 log(10) copies/mL; P=.003) and final values (5.02 vs. 4.34 log(10) copies/mL; P<.001). After adjustment for baseline HIV load and World Health Organization HIV stage, the difference in final HIV load was 0.24 log(10) copies/mL (95% confidence interval, -0.01 to 0.50 log(10) copies/mL; P=.06). CONCLUSIONS: Poor prognosis for HIV-infected individuals after TB may be due to preexisting high HIV load rather than to the TB event itself. An episode of TB was associated with a small adjusted increase in HIV load at the end of the study--an increase that would not be regarded as clinically significant in an individual but could have some effect on HIV disease progression or HIV transmission at the population level. Prevention of TB is important for the reduction of HIV-related morbidity and mortality; however, antiretroviral therapy is required to have a major effect on survival in individuals with HIV disease.

AIDS-Related Opportunistic Infections↗

PubMed2004

Human immunodeficiency virus and the prevalence of undiagnosed tuberculosis in African gold miners.

We hypothesized that rapid presentation may be a general feature of tuberculosis (TB) associated with human immunodeficiency virus (HIV) that limits the impact of HIV on the point prevalence of TB. To investigate this, we performed a cross-sectional HIV and TB disease survey with retrospective and prospective follow-up. HIV prevalence among 1,773 systematically recruited miners was 27%. TB incidence was much more strongly HIV associated (incidence rate ratio, 5.5; 95% confidence interval [CI], 3.5-8.6) than the point prevalence of undiagnosed TB disease (odds ratio, 1.7; 95% CI, 0.9-3.3). For smear-positive TB, 7 of 9 (78%) prevalent cases were HIV negative, and point prevalence was nonsignificantly lower in miners who were HIV positive (odds ratio, 0.8; 95% CI, 0.1-4.2). The calculated mean duration of smear positivity before diagnosis (point prevalence/incidence) was substantially shorter for HIV-positive than HIV-negative TB patients (0.17 and 1.15 years, respectively; ratio, 0.15; 95% CI, 0.00-0.73). HIV has considerably less impact on the point prevalence of TB disease than on TB incidence, probably because rapid disease progression increases presentation and case-finding rates. The difference in mean duration of smear positivity was particularly marked and, if generalizable, will have major implications for TB control prospects in high HIV prevalence areas.

Adolescent↗

PubMed2004

Transmission of HIV-1 infection in sub-Saharan Africa and effect of elimination of unsafe injections.

During the past year, a group has argued that unsafe injections are a major if not the main mode of HIV-1 transmission in sub-Saharan Africa. We review the main arguments used to question the epidemiological interpretations on the lead role of unsafe sex in HIV-1 transmission, and conclude there is no compelling evidence that unsafe injections are a predominant mode of HIV-1 transmission in sub-Saharan Africa. Conversely, though there is a clear need to eliminate all unsafe injections, epidemiological evidence indicates that sexual transmission continues to be by far the major mode of spread of HIV-1 in the region. Increased efforts are needed to reduce sexual transmission of HIV-1.

Adolescent↗

PubMed2004

Asking semi-literate adolescents about sexual behaviour: the validity of assisted self-completion questionnaire (ASCQ) data in rural Tanzania.

OBJECTIVES: To develop and test a sexual behaviour survey method for semi-literate populations, combining the privacy of a self-completion questionnaire (SCQ) with the clarity of a face-to-face questionnaire (FFQ). METHODS: In 1998, 6079 Tanzanian primary school students (mean age 15.1 years) were surveyed using an innovative assisted self-completion questionnaire (ASCQ). The format of the questionnaire was simple, all responses were closed, and conceptually complex questions such as those involving ranking or multiple answers were avoided. The ASCQ was administered to groups of 20 by a research assistant who read questions and answers aloud in two languages so pupils could tick or write responses independently. A total of 4958 of respondents from the 1998 ASCQ Cohort also participated in a 1998 FFQ interview and, in 2000, 4424 again completed an ASCQ. RESULTS: In the 1998 ASCQ survey, 55.0% of males and 21.1% of females reported they had had vaginal intercourse, of whom 71.5% and 66.0%, respectively reported their first sexual relationship lasted for a week or less, and 49.5% and 59.6%, respectively reported they had had sex in the last 4 weeks. After adjustment for age, reported sex was associated with alcohol use in both males (OR = 1.57) and females (OR = 1.69), earning money for males (OR = 1.32) and not living with a mother for females (OR = 0.77). The vast majority of respondents did not appear to have difficulty completing the ASCQ, but 7.4% of 1998 respondents and 2.9% of 2000 respondents selected all first or all last answers in a section for which this was inconsistent. This bias was associated with female, less educated and more geographically remote respondents. Of those respondents who reported sex in the 1998 ASCQ survey, 32.1% reported fewer total partners in the 2000 ASCQ survey, 25.2% reported having had sex fewer times than originally reported, and 61.9% of those who reported having used a condom in 1998 reported never having used one in 2000. While the proportions reporting sex were very similar in the 1998 ASCQ and FFQ surveys, 37.9% of males and 59.2% of females reporting sex only did so on one of the two questionnaires. Higher proportions of respondents reported sensitive information in the ASCQ than the FFQ, although in some cases this may have related to answer order bias. CONCLUSION: The results suggest that an ASCQ may be useful in assessing sexual behaviour in African adolescents, particularly for older, male and/or educated respondents. However, triangulation with data from other surveys raises questions about the validity of self-reported sexual behaviour in general.

Adolescent↗

PubMed2004

Performance of commercially available enzyme immunoassays for detection of antibodies against herpes simplex virus type 2 in African populations.

Data are accumulating on the performance of enzyme immunoassays (EIAs) for the detection of herpes simplex virus type 2 (HSV-2) infection in North America and Europe, but little is known about their performance in other populations. Nine test kits were evaluated with 330 serum samples from sub-Saharan Africa. The tests were first compared to the monoclonal antibody (MAb) EIA (Central Public Health Laboratory, London, United Kingdom). Samples that gave discordant results in the MAb EIA and in the three tests that performed best compared to the MAb EIA were tested by Western blotting (University of Washington, Seattle). A random sample of concordant samples was also tested, and the sensitivities and specificities of the different tests were calculated, taking into account this sampling strategy. The sensitivities of the tests ranged from 86 to 100%; the specificities ranged from 47 to 99%. The tests that performed best were the Gull Premier EIA (sensitivity, 86.3%; specificity, 97.6%) and the Kalon Biological (sensitivity, 92.3%; specificity, 97.7%) and Biokit (sensitivity, 86.7%; specificity, 92.6%) tests. It cannot be assumed that enzyme immunoassays for the detection of HSV-2 infection that perform well in industrialized countries will perform equally well in other populations.

Adolescent↗

PubMed2003

Higher risk behaviour and rates of sexually transmitted diseases in Mwanza compared to Uganda may help explain HIV prevention trial outcomes.

OBJECTIVE: To determine to what extent the higher impact of treatment for sexually transmitted diseases (STD) on HIV incidence in Mwanza, Tanzania than in Rakai and Masaka, Uganda might be explained by baseline differences between the trial populations. DESIGN: A re-analysis of baseline data from the three trial populations comparing demography, sexual risk behaviour and HIV/STD epidemiology. METHODS: Data were compared after age-standardization and adjustments for sample selection where necessary. STD rates were also adjusted for the sensitivities and specificities of the diagnostic techniques used. RESULTS: Demographic patterns were similar across populations, apart from effects of AIDS on fertility and mortality (including widowhood) in Uganda. Higher sexual risk behaviours, including younger age of sexual debut, higher numbers of recent partners and lower frequency of condom use, were apparent in Mwanza compared to Masaka and Rakai. High-titre serological syphilis, gonorrhoea, chlamydia infection and trichomoniasis were all more prevalent in Mwanza, except for chlamydia infection in males. There was little difference between sites in the seroprevalence of Herpes simplex virus type-2. Age patterns in the prevalence of short-duration STD and current risk behaviours were similar across sites but all-titre serological syphilis was more prevalent among older participants in Rakai and Masaka than Mwanza. CONCLUSIONS: Differences between trial populations included higher reported risk behaviour and higher rates of curable STD in Mwanza compared to Rakai and Masaka. These differences probably relate to previous reductions in risk behaviour in Uganda and may explain, at least in part, the contrasting results of these trials.

Adolescent↗

PubMed2003

Stable incidence rates of tuberculosis (TB) among human immunodeficiency virus (HIV)-negative South African gold miners during a decade of epidemic HIV-associated TB.

During the last decade, annual tuberculosis (TB) case-notification rates increased 4-fold, to >4000 cases/100000 person-years, in the study workforce, among whom prevalence of human immunodeficiency virus (HIV) was 30% in 2000. Three separate cohort studies, totalling 6454 HIV-negative participants, were combined and analyzed for time trends. Observed incidence of TB varied between 962 (1991-1994) and 1589 (1999-2000) cases/100000 person-years (P=.17, test for trend). There was, however, a progressive increase in age, and, for each period, older age was associated with increased incidence rates of TB (P<.001). Having adjusted for age differences, there was no significant association between incidence of TB and calendar period (P=.81, test for trend). Relative to 1991-1994, multivariate-adjusted incidence-rate ratios were 0.94, for 1995-1997, 0.96, for 1998-1999, and 1.05, for 1999-2000. Preventing a secondary epidemic of TB among HIV-negative individuals may be achievable with conventional means, even in settings with a high burden of HIV-associated TB.

AIDS-Related Opportunistic Infections↗

PubMed2003

Efficacy of secondary isoniazid preventive therapy among HIV-infected Southern Africans: time to change policy?

OBJECTIVE: To determine the efficacy of secondary preventive therapy against tuberculosis (TB) among gold miners working in South Africa. DESIGN: An observational study. SETTING: Health service providing comprehensive care for gold miners. METHODS: The incidence of recurrent TB was compared between two cohorts of HIV-infected miners: one cohort (n = 338) had received secondary preventive therapy with isoniazid (IPT) and the other had not (n = 221). RESULTS: The overall incidence of recurrent TB was reduced by 55% among men who received IPT compared with those who did not (incidence rates 8.6 and 19.1 per 100 person-years, respectively; incidence rate ratio, 0.45; 95% confidence interval 0.26-0.78). The efficacy of isoniazid preventive therapy was unchanged after controlling for CD4 cell count and age. The number of person-years of IPT required to prevent one case of recurrent TB among individuals with a CD4 cell count < 200 x 106 cells/l, and > or = 200 x 106 cells/l was 5 and 19, respectively. CONCLUSION: Secondary preventive therapy reduces TB recurrence: the absolute impact appears to be greatest among individuals with low CD4 cell counts. International TB preventive therapy guidelines for HIV-infected individuals need to be expanded to include recommendations for secondary preventive therapy in settings where TB prevalence is high.

Adult↗

PubMed2002

School based HIV prevention in Zimbabwe: feasibility and acceptability of evaluation trials using biological outcomes.

OBJECTIVE: To determine the feasibility and acceptability of conducting a community randomized trial (CRT) of an adolescent reproductive health intervention (ARHI) using biological measures of effectiveness. SETTING: Four secondary schools and surrounding communities in rural Zimbabwe. METHODS: Discussions were held with pupils, parents, teachers and community leaders to determine acceptability. A questionnaire and urine sampling survey was undertaken among Form 1 and 2 pupils. Studies were undertaken to inform likely participation and follow up in a future CRT. A community survey of 16-19-year-olds was conducted to determine levels of secondary school attendance and likely HIV prevalence at final follow up in the event of a trial. RESULTS: Form 1 and 2 pupils aged 12-18 years (n = 723; median age, 15 years) participated in the research. Prevalences of HIV, Chlamydia and gonorrhoea were 3.6% [95% confidence interval (CI), 2.3-5.3%], 0.4% (95% CI, 0.1-1.3%) and 1.9% (95% CI, 1.0-3.3%) respectively. There was poor correlation between biological evidence of sexual experience and questionnaire responses, due to concerns about confidentiality. Only 13% (95% CI, 4-27%) of those infected with HIV and/or a sexually transmitted disease admitted to having had sex. In the community survey of 573 adolescents aged 16-19 years, 6.6% (95% CI, 3.9-10.3%) of females and 5.1% (95% CI, 2.9-8.2%) of males were HIV positive. High participation and retention rates are achievable within a trial in this setting. CONCLUSIONS: It is acceptable and feasible to conduct randomized trials to establish the effectiveness of ARHIs. However, self-reported behavioural outcomes will probably be biased, emphasizing the importance of using externally validated biological outcome measures to determine effectiveness.

Adolescent↗

PubMed2002

HIV-1/AIDS and the control of other infectious diseases in Africa.

The effect of HIV-1 on other infectious diseases in Africa is an increasing public health concern. In this review, we describe the role that three major infectious diseases--malaria, sexually transmitted diseases (STDs), and tuberculosis--have had in the HIV-1 epidemic. The high prevalence of untreated STD infections has been a major factor facilitating the spread of HIV-1 in Africa; with the synergistic interaction between HIV-1 transmission and genital herpes being of special concern for control of both diseases. Increased susceptibility to tuberculosis after infection with HIV-1 has led to a rising incidence and threat of increased transmission of tuberculosis. Clinical malaria occurs with an increased frequency and severity in HIV-1-infected individuals, especially during pregnancy. As with tuberculosis, STDs, and other communicable HIV-1-associated diseases, the net effect of HIV-1 might include increased rates of malaria transmission across communities. In addition to enhancing access to HIV-1 prevention and care, public health surveillance and control programmes should be greatly intensified to cope with the new realities of infectious disease control in Africa.

AIDS-Related Opportunistic Infections↗

PubMed2002

Morbidity and mortality in South African gold miners: impact of untreated disease due to human immunodeficiency virus.

A cohort of 1792 human immunodeficiency virus (HIV)-positive and 2970 HIV-negative South African miners was observed for 12 months starting in February 1998. All-cause hospitalizations and deaths were significantly associated with HIV infection (respective unadjusted incidence rate ratios, 2.9 and 9.2; respective 95% confidence intervals, 2.5-3.4 and 5.5-16.0). Tuberculosis (TB), bacterial pneumonia, cryptococcosis, and trauma were the major causes of admission for HIV-positive patients, whereas Pneumocystis carinii pneumonia was an uncommon cause (respective admission rates, 8.5, 6.9, 2.2, 6.0, and 0.53 admissions per 100 person-years). Enteritis, bronchitis, urinary tract infections, and soft-tissue infections were also significantly associated with HIV infection. Cryptococcosis caused 44% of deaths among HIV-positive patients. Trauma was the main hazard for HIV-negative men, causing 42% of admissions and 60% of deaths. A broad range of infectious conditions is significantly associated with HIV infection in South African miners. Identification and implementation of effective prophylactic regimens are urgently needed.

Adult↗