Survival probability and factors associated with time to loss to follow-up and mortality among patients on antiretroviral treatment in central Kenya.

BACKGROUND: Retention of patients who are receiving antiretroviral therapy (ART) remains a challenge especially in the setting of rapid expansion of HIV services. Retention in care remains vital to the HIV care continuum, and has been associated with viral suppression and improved survival. This study aimed to ascertain survival rates, time to loss to follow-up (LTFU) or mortality events and factors associated with time to LTFU or mortality among patients enrolled on antiretroviral therapy at health facilities in central Kenya. METHODS: This was a retrospective cohort study among patients initiated on ART between 2004 and 2012 in central Kenya. Demographic characteristics, clinical characteristics and outcomes data were analyzed using Stata version 15.1. Competing risks regression analysis and cummulative incidence functions were used to estimate survival. RESULTS: A total of 31,346 patients were included, of whom 65.6% were female, 76.0% were aged between 20 and 50 years old, and 38.9% were diagnosed at WHO stage III. At 36 months, overall retention was 68.8%, LTFU was 27.1%, and mortality was 4.1%. The total person-years of follow up was 74,986. The incidence rate of LTFU was 9.99 per 100 person years for a total of 9383.25 person-years of follow up. The mortality rate was 1.25 per 100 person years for a total of 875.5 person-years among those who died. The median time to LTFU was 11 months (IQR 3-22) while median time to death was 3 months (IQR 0-13). Men, unmarried patients, patients presenting with advanced HIV, not on TB treatment, and enrolled into the HIV program in later cohorts, had a shorter time to mortality and LTFU. CONCLUSION: Our study demonstrated evidence of scale-up of HIV treatment programs in central Kenya. While most patients were enrolled at an advanced WHO clinical stage, overall 36-month mortality remained low, but occurred earlier during follow-up. Cohort LTFU at 36-months reduced in later years with the losses occurring within the 1st year of follow-up. Predictors of early mortality and LTFU included being male, single, separated or divorced, advanced WHO clinical stage, and among patients not on TB treatment.

HLA class I associations with rates of HIV-1 seroconversion and disease progression in the Pumwani Sex Worker Cohort.

Class I human leukocyte antigens (HLA) play an important role in the adaptive immune response by presenting antigens to CD8+ T cells. Studies have reported that several HLA class I alleles are associated with differential disease progression in human immunodeficiency virus (HIV)-infected individuals, however, few class I associations with resistance or susceptibility to HIV-1 infection have been reported. We typed HLA-A, -B and -C of >1000 women enrolled in the Pumwani Sex Worker Cohort using a sequence-based typing method. Kaplan-Meier analysis was used to identify alleles influencing seroconversion and disease progression to acquired immune deficiency syndrome (CD4 < 200/mm³). A*01 (P = 0.020), C*06:02 (P = 0.042) and C*07:01 (P = 0.050) are independently associated with protection from seroconversion. Women with any of these alleles are less likely to seroconvert [P = 0.00001, odds ratio (OR): 0.503, 95% confidence interval (CI): 0.320-0.790]. Conversely, A*23:01 (P = 0.004), B*07:02 (P = 0.003) and B*42:01 (P = 0.025) are independently associated with rapid seroconversion. Women with any of these alleles are twice as likely to seroconvert (P = 0.002, OR: 2.059, 95% CI: 1.290-3.285). The beneficial alleles confer threefold protection from seroconversion when compared with the susceptible alleles (P = 0.000001, OR: 0.268, 95% CI: 0.132-0.544). B*07:02 is the contributing allele, within the B7 supertype, to the rapid seroconversion. A*74:01 (P = 0.04/P = 0.006), B*14 (P = 0.003/P = 0.003) and B*57:03 (P = 0.012/P = 0.038) are independently associated with slower CD4+ decline and LTNP phenotype, while B*07:02 (P = 0.020), B*15:10 (P = 0.022) and B*53:01 (P = 0.007) are independently associated with rapid CD4+ T-cell decline. B7 supertype (P = 0.00006), B*35*-Py (P = 0.028) and B*35-Px (P = 0.001) were also significantly associated with rapid CD4+ T-cell decline. Understanding why these HLA class I alleles are associated with protection/susceptibility to HIV-1 acquisition and disease progression could contribute to the development of effective prophylactic and therapeutic vaccines for HIV-1.

Trends in TB and HIV care and treatment cascade, Kenya, 2008-2018.

BACKGROUND: HIV infection is associated with high mortality among people with TB. Antiretroviral therapy (ART) reduces TB incidence and mortality among people living with HIV (PLHIV). Since 2005, Kenya has scaled up TB and HIV prevention, diagnosis and treatment. We evaluated the impact of these services on trends and TB treatment outcomes.METHODS: Using Microsoft Excel (2016) and Epi-Info 7, we analysed Kenya Ministry of Health TB surveillance data from 2008 to 2018 to determine trends in TB notifications, TB classification, HIV and ART status, and TB treatment outcomes.RESULTS: Among the 1,047,406 people reported with TB, 93% knew their HIV status, and 37% of these were HIV-positive. Among persons with TB and HIV, 69% received ART. Between 2008 and 2018, annual TB notifications declined from 110,252 to 96,562, and HIV-coinfection declined from 45% to 27%. HIV testing and ART uptake increased from 83% to 98% and from 30% to 97%, respectively. TB case fatality rose from 3.5% to 3.9% (P <0.018) among HIV-negative people and from 5.1% to 11.2% (P <0.001) among PLHIV on ART.CONCLUSION: TB notifications decreased in settings with suboptimal case detection. Although HIV-TB services were scaled-up, HIV-TB case fatality rose significantly. Concerted efforts are needed to address case detection and gaps in quality of TB care.

Can isoniazid preventive therapy be scaled up rapidly? Lessons learned in Kenya, 2014-2018.

BACKGROUND: TB is the leading cause of mortality among people living with HIV (PLHIV), for whom isoniazid preventive therapy (IPT) has a proven mortality benefit. Despite WHO recommendations, countries have been slow in scaling up IPT. This study describes processes, challenges, solutions, outcomes and lessons learned during IPT scale-up in Kenya.METHODS: We conducted a desk review and analyzed aggregated Ministry of Health (MOH) IPT enrollment data from 2014 to 2018 to determine trends and impact of program activities. We further analyzed IPT completion reports for patients initiated from 2015 to 2017 in 745 MOH sites in Nairobi, Central, Eastern and Western Kenya.RESULTS: IPT was scaled up 75-fold from 2014 to 2018: the number of PLHIV covered increased from 9,981 to 749,890. The highest percentage increases in the cumulative number of PLHIV on IPT were seen in the quarters following IPT pilot projects in 2014 (49%), national launch in 2015 (54%), and HIV treatment acceleration in 2016 (158%). Among 250,069 patients initiating IPT from 2015 to 2017, 97.5% completed treatment, 0.2% died, 0.8% were lost to follow-up, 1.0% were not evaluated, and 0.6% discontinued treatment.CONCLUSIONS: IPT can be scaled up rapidly and effectively among PLHIV. Deliberate MOH efforts, strong leadership, service delivery integration, continuous mentorship, stakeholder involvement, and accountability are critical to program success.

Epidemiologic evidence for the development of serovar-specific immunity after gonococcal infection.

We tested the hypothesis that strain-specific immunity occurs after gonococcal infection in a longitudinal study of 227 prostitutes resident in one small community who experienced frequent gonococcal infections. Women were examined and cultured for Neisseria gonorrhoeae at 2-wk intervals. Gonococcal isolates were typed according to protein 1 serovar, auxotype, and beta-lactamase plasmid type, and classified as to serovar and strain. The hypothesis was tested by comparing the predictions of the hypothesis with the observations of the study. Over the 14-mo period of the study, major changes in the prevalence of specific serovars were observed in the gonococcal population infecting these women. Women with HIV infection experienced a higher rate of gonococcal infection (0.56 +/- 0.03 vs. 0.46 +/- 0.04, P less than 0.05, t test) compared with HIV-negative women and were more likely to experience multiple infections with the same strain. The duration of prostitution was inversely related to the frequency of gonococcal infection. Women experiencing an infection with a specific gonococcal serovar were at a 2- to 10-fold reduced risk of reinfection with the same serovar, except for the 1B-1 serovar. The results of the study were consistent with all four predictions of the hypothesis. Infection with a specific gonococcal serovar results in specific but incomplete protection against subsequent infection with the homologous serovar. The mechanism of this protection remains to be determined.

Cytotoxic T cell responses to multiple conserved HIV epitopes in HIV-resistant prostitutes in Nairobi.

Many people who remain persistently seronegative despite frequent HIV exposure have HIV-specific immune responses. The study of these may provide information about mechanisms of natural protective immunity to HIV-1. We describe the specificity of cytotoxic T lymphocyte responses to HIV in seronegative prostitutes in Nairobi who are apparently resistant to HIV infection. These women have had frequent exposure to a range of African HIV-1 variants, primarily clades A, C, and D, for up to 12 yr without becoming infected. Nearly half of them have CTL directed towards epitopes previously defined for B clade virus, which are largely conserved in the A and D clade sequences. Stronger responses are frequently elicited using the A or D clade version of an epitope to stimulate CTL, suggesting that they were originally primed by exposure to these virus strains. CTL responses have been defined to novel epitopes presented by HLA class I molecules associated with resistance to infection in the cohort, HLA-A*6802 and HLA-B18. Estimates using a modified interferon-gamma Elispot assay indicate a circulating frequency of CTL to individual epitopes of between 1:3,200 and 1:50,000. Thus, HIV-specific immune responses-particularly cross-clade CTL activity- may be responsible for protection against persistent HIV infection in these African women.

The importance of core groups in the epidemiology and control of HIV-1 infection.

PIP: In Africa, HIV transmission occurs mainly through heterosexual intercourse. High-frequency transmitter core groups are key to the epidemiology of HIV-1 and STD on the continent. The rapid growth of the HIV-1 epidemic in Africa appears to have resulted, in part, from social and economic factors which result in individuals' frequent engagement in sexual intercourse with members of HIV-infected core groups. Understanding the importance of core groups in HIV-1 transmission is therefore key to developing more effective programs for the control of HIV-1. Sections explore the core groups concept and the sexual transmission of infection, social and economic forces creating core groups in Africa, the interaction of STD and HIV-1 in core groups, the effect of STD on HIV-1 disease progression in core groups in accelerating the HIV-1 epidemic, the role of core group interventions in control programs, balancing disease control with the potential for victimization, and research needs.^ieng

Controlling HIV in Africa: effectiveness and cost of an intervention in a high-frequency STD transmitter core group.

Since 1985, a population of over 1,000 predominantly HIV-positive female prostitutes residing in a low-income area of Nairobi, has been enrolled in a sexually transmitted disease (STD)/HIV control programme. The major elements of the programme include the diagnosis and treatment of conventional STD, and the promotion of condom use to prevent the transmission of HIV and other sexually transmitted infections. Using estimates of numbers of HIV-seropositive prostitutes, numbers of sexual contacts, susceptibility of clients to HIV, HIV transmission efficiency, rates of condom use and the basic reproductive rate of HIV infection in Kenya, we estimate that the programme is responsible for preventing between 6,000 and 10,000 new cases of HIV infection per year among clients and contacts of clients. The total annual operating cost of the programme is approximately US$77,000 or between US$8.00 and US$12.00 for each case of HIV infection prevented. Programmes to reduce the transmission of HIV and other sexually transmitted infections which are targeted at high-frequency STD transmitters, such as prostitutes, can be effective and relatively inexpensive to undertake. More such programmes should be developed and evaluated in different settings.

Stable antenatal HIV-1 seroprevalence with high population mobility and marked seroprevalence variation among sentinel sites within Nairobi, Kenya.

OBJECTIVES: To monitor and analyse trends in HIV-1 seroprevalence among antenatal women in Nairobi, Kenya. DESIGN: Six sequential surveys were carried out among antenatal clinic attenders at four Nairobi City Council health centres between November 1991 and April 1997. METHODS: A total of 6828 women attending for first antenatal clinic visit were administered a standard questionnaire to obtain demographic information and were screened for HIV-1. RESULTS: HIV-1 seroprevalence rose from 12.1% in the first survey to 16.2% in the third, completed in October 1993. No rise was observed in subsequent surveys, and seroprevalence among women under the age of 20 declined after the third survey. Significant differences in seroprevalence (P < 0.001) were observed in all survey rounds between women who reported that their province of origin was Nyanza (22.4% overall), compared with those from other provinces in western Kenya (14.1%), and the eastern group of provinces (8.9%). The rise in HIV-1 seroprevalence observed between 1991 and 1993 was almost entirely attributable to the rising seroprevalence among women from Nyanza. There were considerable differences in HIV-1 seroprevalence among the four health centres, partly accounted for by differences in the proportion of clinic attenders from different provinces of origin, which also changed significantly over time. CONCLUSIONS: HIV-1 seroprevalence has stabilized in antenatal women attending these health centres in Nairobi, and may be declining among women in the youngest age group. This may reflect stabilization of HIV-1 incidence, but further observation is required. The levels of infection among Nairobi residents reflect the evolution of the HIV epidemic in their provinces of origin, and changing client composition influences HIV-1 seroprevalence at different clinics. HIV sentinel surveillance should be carried out at multiple sites in large urban centres to monitor accurately the evolution of the HIV epidemic and the impact of control efforts in reducing transmission.

Transition dynamics of HIV disease in a cohort of African prostitutes: a Markov model approach.

The progression of HIV-related disease from infection to death is represented as a staged Markov model. Transitions between stages are considered reversible. The model is fitted to data from a cohort of African prostitutes by means of maximum likelihood. It appears that the progression to symptomatic disease (Centers for Disease Control stage IV) in this population is considerably more rapid than that reported from studies in Western countries.

PIP: Identifying the incubation period of HIV infection is important for individual prognoses, for developing and testing intervention strategies, for determining the reproductive rate of the disease, and for prevalence of the disease. Mathematical modeling of HIV infection in Africa is necessitated because the disease is more widespread and the immune system is constantly active due to the exposure to diseases such as malaria and tuberculosis. The Markov model for this analysis was selected because parametric estimation is not based on the time a stage is entered, but on the duration between observations and the stages at the time of observation. The HIV infected female prostitutes in the Pumwani area of Nairobi, Kenya (a population primarily of Tanzanian origin) have been identified as a study population since 1985, and seen every 6 months in clinic, or as needed. Data are constricted by the movement out of the area in the end stage of disease, which is only partially solved by tracking with community health workers. The stages identified in incubation estimation are stage 1: seropositive but symptom free (CDC stage II); stage 2: generalized lymphadenopathy (CDC stage III); stage 3: symptomatic disease (CDC stage IV); and stage 4: death. Data reflect the movement back and forth between stage 1 and 2, between 2 and 3, so the model is not a pure Longini model but rather a timed homogeneous staged model with reversible stages called transition parameters computed in a numerical differentiation. The Fortran computer program for the analyses is available from the authors. The results suggest a quick transition between seroconversion and lymphadenopathy (2.4 months) and unlikely reversal, with the mean waiting time until passage to stage 3 is approximately 2.6 years and conversions are common. Since opportunistic infections are treatable, this makes sense. Assuming a correct model, the estimation of the transition time of 20 months of h34 value of .01 and .05, the mean passage time from stage 1, 2, 3 to 4 (death) is 9.1, 8.9, and 6.2 years 12.9, 12.7, and 10.1 years respectively. The implications are that 1) when infectiousness is hypothesized to be not uniform, peak infectivity occurs earlier in Africa than in the West at least among prostitutes, or 2) if infectivity is constant throughout the incubation period, then HIV transmission must be higher in Africa to explain the high rate of infection.

HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan sex workers.

OBJECTIVES: Most HIV-1 transmission is sexual; therefore, immune responses in the genital mucosa may be important in mediating protection against HIV infection. This study examined HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan female sex workers. METHODS: HIV-1-specific immune responses were compared in HIV-1-resistant and HIV-1-infected sex workers, and in lower risk uninfected women. Cervical and vaginal samples from each group were tested for HIV-1-specific IgA and IgG by enzyme immunoassay. Systemic T-helper lymphocyte cell responses to HIV-1 envelope peptide epitopes were assayed using an interleukin 2 bioassay. HIV-1 risk-taking behaviours were assessed using standardized questionnaires. RESULTS: HIV-1-specific IgA was present in the genital tract of 16 out of 21 (76%) HIV-1-resistant sex workers, five out of 19 (26%) infected women, and three out of 28 (11%) lower risk women (P < 0.0001). Among lower risk women, the presence of HIV-1-specific IgA was associated with HIV-1 risk-taking behaviour. Systemic T-helper lymphocyte responses to HIV-1 envelope peptides were present in 11 out of 20 (55%) HIV-1-resistant women, four out of 18 (22%) infected women, and one out of 25 (4%) lower risk women (P < 0.001). T-helper lymphocyte responses did not correlate with the presence or titre of virus-specific mucosal IgA in any study group. CONCLUSIONS: HIV-1-specific IgA is present in the genital tract of most HIV-1-resistant Kenyan sex workers, and of a minority of lower risk uninfected women, where it is associated with risk-taking behaviour. These data suggest a role for mucosal HIV-1-specific IgA responses in HIV-1 resistance, independent of host cellular responses.

HIV infection among lower socioeconomic strata prostitutes in Nairobi.

A cohort of 418 lower socioeconomic strata prostitutes were enrolled in a study of the epidemiology of sexually transmitted diseases (STDs) between January and April 1985. Sixty-two per cent of the women were seropositive for HIV infection at enrollment. Significant associations were found between HIV seropositivity and Tanzanian origin (OR = 2.12, CI 95% = 1.18-3.81, P less than 0.03), younger age, a shorter duration of prostitution, reduced fecundity, use of oral contraceptives (OR = 1.8, CI 95% = 1.1-2.9, P less than 0.05) and genital ulcer disease (OR = 3.32, P less than 0.00001). No associations were noted with other STD. Stepwise logistic regression analysis confirmed independent associations between HIV infection and Tanzanian origin (OR = 2.27, CI 95% = 1.25-4.14, P less than 0.007), reduced fecundity (OR = 0.83, CI 95% = 0.74-0.94, P less than 0.003), oral contraceptive use (OR = 2.02, CI 95% = 1.22-3.35, P less than 0.006) and duration of prostitution (OR = 0.39, CI 95% = 0.23-0.65, P less than 0.004). Oral contraceptives may increase susceptibility to HIV or may be a marker for other factors which increase risk of acquisition. Further studies are necessary to confirm this association.

Isoniazid preventive therapy for tuberculosis in HIV-1-infected adults: results of a randomized controlled trial.

OBJECTIVES: To determine the efficacy of isoniazid 300 mg daily for 6 months in the prevention of tuberculosis in HIV-1-infected adults and to determine whether tuberculosis preventive therapy prolongs survival in HIV-1-infected adults. DESIGN AND SETTING: Randomized, double-blind, placebo-controlled trial in Nairobi, Kenya. SUBJECTS: Six hundred and eighty-four HIV-1-infected adults. MAIN OUTCOME MEASURES: Development of tuberculosis and death. RESULTS: Three hundred and forty-two subjects received isoniazid and 342 received placebo. The median CD4 lymphocyte counts at enrolment were 322 and 346 x 10(6)/l in the isoniazid and placebo groups, respectively. The overall median follow-up from enrolment was 1.83 years (range, 0-3.4 years). The incidence of tuberculosis in the isoniazid group was 4.29 per 100 person-years (PY) of observation [95% confidence interval (CI) 2.78-6.33] and 3.86 per 100 PY of observation (95% CI, 2.45-5.79) in the placebo group, giving an adjusted rate ratio for isoniazid versus placebo of 0.92 (95% CI, 0.49-1.71). The adjusted rate ratio for tuberculosis for isoniazid versus placebo for tuberculin skin test (TST)-positive subjects was 0.60 (95% CI, 0.23-1.60) and for the TST-negative subjects, 1.23 (95% CI, 0.55-2.76). The overall adjusted mortality rate ratio for isoniazid versus placebo was 1.18 (95% CI, 0.79-1.75). Stratifying by TST reactivity gave an adjusted mortality rate ratio in those who were TST-positive of 0.33 (95% CI, 0.09-1.23) and for TST-negative subjects, 1.39 (95% CI, 0.90-2.12). CONCLUSIONS: Overall there was no statistically significant protective effect of daily isoniazid for 6 months in the prevention of tuberculosis. In the TST-positive subjects, where reactivation is likely to be the more important pathogenetic mechanism, there was some protection and some reduction in mortality, although this was not statistically significant. The small number of individuals in this subgroup made the power to detect a statistically significant difference in this subgroup low. Other influences that may have diluted the efficacy of isoniazid include a high rate of transmission of new infection and rapid progression to disease or insufficient duration of isoniazid in subjects with relatively advanced immunosuppression. The rate of drug resistance observed in subjects who received isoniazid and subsequently developed tuberculosis was low.

Health outreach and control of HIV infection in Kenya.

This paper highlights the role of mobilization of individuals and community groups and health professionals in prevention of HIV transmission. It traces the educational strategy employed to reach the general population and selected groups at risk. In Kenya, the general awareness about AIDS started to grow in late 1985 and increased in 1986-87. This has resulted in reduction of the incidence of some sexually transmitted diseases (STDs). The importance of pretesting education material as well as monitoring and evaluation of educational efforts to lay the ground for culturally appropriate and more effective health education messages to combat HIV transmission is presented. The paper concludes by emphasizing the importance of developing the HIV infection programs with the people and for the people.

Human leucocyte antigen supertypes and immune susceptibility to HIV-1, implications for vaccine design.

T cell responses against HIV-1 have been identified in a number of exposed uninfected populations. We hypothesized that the ability to mount an effective T cell response is partly determined by the human leucocyte antigens (HLA) phenotype of the individual. We examined whether certain HLA supertypes were associated with differential HIV-1 susceptibility in sexually exposed adults and in the setting of mother to child HIV-1 transmission. By multivariate analysis, decreased HIV-1 infection risk was strongly associated with possession of a cluster of closely related class I HLA alleles (A2/6802 supertype) in sexually exposed adults (Hazard ratio=0.42, 95% confidence intervals (CI): 0.22-0.81, P=0.009) and perinatally exposed infants (Odds ratio=0.12, 95% CI: 0.03-0.54, P=0.006). The alleles in this HLA supertype are known in some cases, to present the same peptide epitopes (termed 'supertopes'), for T cell recognition. The identification of HIV-1 supertopes, which are associated with protection from HIV-1 infection, has important implications for the application of epitope-based HIV-l vaccines in a variety of racial groups.

The Nairobi STD program. An international partnership.

Since 1980, Canadian, Belgian, and American scientists have been working together with colleagues in Kenya to understand the epidemiology and biology of sexually transmitted diseases (STDs) in Africa. The rapid spread of human immunodeficiency virus has dramatically increased the importance of this information. Interventions to slow the spread of all STDs and to reduce their consequences are now our major priority. However, this will require continuing research, ongoing training of scientists, epidemiologists, and technologists, and increasing financial support from industrialized societies.

Decentralisation of tuberculosis treatment from the main hospitals to the peripheral health units and in the community within Machakos district, Kenya.

SETTING: A rural district, Machakos, in Kenya, facing decreasing national resources for health and an increasing tuberculosis (TB) caseload fuelled by the human immunodeficiency virus (HIV). OBJECTIVE: To evaluate the impact on district TB programme performance of decentralising TB treatment by providing ambulatory care in the hospital and peripheral health units and in the community. METHODS: A comparative study of district TB programme performance before and after the decentralisation of TB services at the end of 1997. To facilitate ambulatory care, ethambutol replaced streptomycin in the new treatment regimen. FINDINGS: The number of patients registered in the control period (1996) was 1141, of whom almost 100% were admitted during the intensive phase of TB treatment, and in the intervention period (1998 and 1999), it was 3244, of whom only 153 (4.7%) required admission in the intensive phase. Of 3244 TB patients (all forms) registered in the intervention period, the number (%) choosing the different options for directly observed treatment (DOT) supervision were: hospital clinic 1618 (49.9%), peripheral health unit 904 (27.9%), community volunteer 569 (17.5%) and hospitalisation 153 (4.7%). The options were found to be acceptable to patients, their families and health staff. The treatment outcomes among new sputum smear-positive pulmonary TB patients were similar in the intervention and control cohorts, with treatment success rates of 88% vs. 85% and death rates of 4% vs. 6%, respectively. Treatment completion was significantly higher among new sputum smear-negative and extra-pulmonary TB patients in the intervention than in the control cohort (79% vs. 48%, respectively). CONCLUSION: The decentralisation of the intensive phase of TB treatment resulted in maintenance of good TB programme performance, while Machakos hospital closed its TB wards. A separate paper describes the cost-effectiveness of this approach. The National Tuberculosis Control Programme plans to adopt this approach as national policy.

Sexual behaviour in Kenya: implications for sexually transmitted disease transmission and control.

Sexual behaviour in Kenya in relation to STD transmission was investigated with a view to forming a basis for the more rational design of STD/HIV control interventions. Questionnaires were administered to a sample of 762 men and women attending eight health facilities in two urban centres. Equal numbers of STD patients (cases) and non-STD related clinic attenders (clinic controls) were selected, matched by gender and clinic. Another sample of 427 men and women was obtained from a random sampling of households in a slum area in Nairobi (community controls). Male STD patients who were unmarried, or married but living apart from their wives, reported a higher mean number of sex partners in the previous three months than did male clinic or community controls. Unmarried female STD patients reported a higher mean number of sex partners in the previous three months than did unmarried female clinic or community controls. Both male and female STD patients were more likely to report having been involved in commercial sex transactions in the previous three months than clinic or community controls. Considerable heterogeneity in sexual behaviour was apparent. In multivariate analysis, the most important predictor of STD acquisition for both men and women was the number of reported sex partners in the previous three months. In addition, for men only, marital status (unmarried, or married but living apart from their wives) and purchasing sex were significant predictors of being an STD patient. These data confirm the importance of commercial sex in STD transmission, and suggest that men play a bridging role between female sex workers and the general population of women.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized, placebo-controlled trial of monthly azithromycin prophylaxis to prevent sexually transmitted infections and HIV-1 in Kenyan sex workers: study design and baseline findings.

Our objectives were to describe the baseline findings of a trial of antibiotic prophylaxis to prevent sexually transmitted infections (STIs) and HIV-1 in a cohort of Nairobi female sex workers (FSWs). A questionnaire was administered and a medical examination was performed. HIV-negative women were randomly assigned to either one gram azithromycin or placebo monthly. Mean age of the 318 women was 32 years, mean duration of sex work 7 years and mean number of clients was 4 per day. High-risk behaviour was frequent: 14% practised anal intercourse, 23% sex during menses, and 3% used intravenous drugs. While 20% reported condom use with all clients, 37% never use condoms. However, STI prevalence was relatively low: HIV-1 27%, bacterial vaginosis 46%, Trichomonas vaginalis 13%, Neisseria gonorrhoeae 8%, Chlamydia trachomatis 7%, syphilis 6% and cervical intraepithelial neoplasia (CIN) 3%. It appears feasible to access a population of high-risk FSWs in Nairobi with prevention programmes, including a proposed trial of HIV prevention through STI chemoprophylaxis.