Assessing the potential of condom use to prevent the spread of HIV: a microsimulation study

In this study, a microsimulation model is used to assess the potential impact of condom use on women's lifetime risk of acquiring HIV in rural southern Malawi. The model draws on survey data for information on sexual activity, marriage and divorce, and on the biomedical literature for input parameters governing the transmission and spread of HIV and other sexually transmitted diseases (STDs). We show that lifetime risk could be as high as 42 percent with no condom use and as low as 8 percent if everyone consistently uses condoms with nonmarital partners. Next, we examine the impact of more realistic, intermediate strategies of condom use, varying men's propensity to use a condom with nonmarital partners, varying the per-coitus probability of condom use, varying probabilities of slippage or breakage, and finally, examining the effect of condom use in the presence of STD symptoms. We demonstrate profound effects of consistent condom use and of condom use prompted by symptomatic STDs.     

The male street prostitute: a vector for transmission of HIV infection into the heterosexual world

Two hundred and eleven New Orleans male street prostitutes were interviewed and tested for antibodies to the human immunodeficiency virus (HIV). The subjects' lifestyle characteristics and their sex and drug use practices were evaluated to determine the prostitutes' potential to function as a vector for transmission of HIV into populations with currently low infection rates. Information about the customers of the male prostitutes was also obtained from the sample. The period prevalence of HIV in the sample was 175/1000. Many of the male prostitutes reported having wives or girlfriends, some of whom were prostitutes themselves. The prostitutes perceived a majority of their male customers to be heterosexual or bisexual (indicating sexual contact with women as well as men), many (39%) were thought to be married. Results from the study support the argument that male prostitutes serve as a bridge of HIV infection into populations with currently low infection rates through contact with both non-customer sexual partners and customers and thus indirectly to spouses and sexual partners of these individuals.     

Aetiology of peptic ulcer: a prospective population study in Norway.

STUDY OBJECTIVE--To analyse simultaneously the effect of several risk factors for peptic ulcer. DESIGN--Cohort study where all patients with new or incident peptic ulcers in a well defined population were registered for a seven year period. The follow up started with a comprehensive health survey including a questionnaire on diet, lifestyle, psychological and social conditions, and health. Relative risks, both sex specific and separate, for gastric and duodenal ulcers were estimated from proportional hazard regression analysis. SETTING--A population based survey conducted in the municipality of Tromsø, northern Norway. PARTICIPANTS--In 1980, a total of 21,440 men and women, aged 20 to 54 years and 20 to 49 years respectively, were invited to participate. A total of 14,667 people attended and returned the questionnaire. MAIN RESULTS--A total of 328 people had their first peptic ulcer in the follow up period. Age, cigarette smoking, first degree relatives with peptic ulcer, and low educational level were shared risk factors for peptic ulcer in both men and women. In men, frequent upper respiratory infections increased the risk of gastric ulcer and drinking a great deal of milk increased the risk of duodenal ulcer. None of the other dietary variables, including coffee and alcohol consumption, contributed significantly to the risk. Use of analgesics was not a risk factor, and none of the psychological indicators analysed carried any significant risk. CONCLUSIONS--Age, inheritance, and cigarette smoking are all important risk factors for peptic ulcer. The increased risk associated with low educational background indicate that social strains, comprising lifestyle and diet habits, are part of the multifactorial aetiology of peptic ulcer. No support was found for the assumption that peptic ulcer disease is a psychosomatic disorder. This study did not support the view that duodenal and gastric ulcers have different aetiologies-rather it showed a similarity in risk patterns.     

HIV-relevant sexual behavior among a healthy inner-city heterosexual adolescent population in an endemic area of HIV

The AIDS crisis has devastated segments of the population including the gay community and those who use intravenous drugs. HIV has spread to other groups including prostitutes and those with other sexually transmitted diseases. We have been studying adolescents in a major Northeast city where there is a major HIV/AIDS epidemic. Despite high levels of AIDS related knowledge, these adolescents reported high levels of sex risk behaviors. In addition, our data suggests that even moderate alcohol or marijuana use predicts high risk sexual behaviors. These data indicate the urgent need to develop prevention strategies for the spread of HIV among inner-city youth based upon relevant predictors of risk behaviors. The coupling of HIV in inner-city populations with a high frequency of risk behaviors in adolescents demands an immediate public health response.     

The efficacy of a relationship-based HIV/STD prevention program for heterosexual couples

OBJECTIVES: This study examined the efficacy of a relationship-based HIV/sexually transmitted disease prevention program for heterosexual couples and whether it is more effective when delivered to the couple or to the woman alone. METHODS: Couples (n = 217) were recruited and randomized to (1) 6 sessions provided to couples together (n = 81), (2) the same intervention provided to the woman alone (n = 73), or (3) a 1-session control condition provided to the woman alone (n = 63). RESULTS: The intervention was effective in reducing the proportion of unprotected and increasing the proportion of protected sexual acts. No significant differences in effects were observed between couples receiving the intervention together and those in which the woman received it alone. CONCLUSIONS: This study demonstrates the efficacy of a relationship-based prevention program for couples at risk for HIV infection.     

The effectiveness of condoms in reducing heterosexual transmission of HIV

CONTEXT: It is not established whether the condom is as effective at preventing heterosexual transmission of HIV as it is for preventing conception. An overall estimate of condom effectiveness for HIV prevention is needed. METHODS: Information on condom usage and HIV serology was obtained from 25 published studies of serodiscordant heterosexual couples. Condom usage was classified as always (in 100% of acts of intercourse), sometimes (1-99%, 0-99% or 1-100%) or never (0%). Studies were stratified by design, direction of transmission and condom usage group. Condom efficacy was calculated from the HIV transmission rates for always-users and never-users. RESULTS: For always-users, 12 cohort samples yielded a consistent HIV incidence of 0.9 per 100 person-years (95% confidence interval, 0.4-1.8). For 11 cohort samples of never-users, incidence was estimated at 6.8 per 100 person-years (95% confidence interval, 4.4-10.1) for male-to-female transmission, 5.9 per 100 (95% confidence interval, 1.5-15.1) for female-to-male transmission and 6.7 per 100 (95% confidence interval, 4.5-9.6) in samples that specified the direction of transmission. Generally, the condom's effectiveness at preventing HIV transmission is estimated to be 87%, but it may be as low as 60% or as high as 96%. CONCLUSIONS: Consistent use of condoms provides protection from HIV. The level of protection approximates 87%, with a range depending upon the incidence among condom nonusers. Thus, the condom's efficacy at reducing heterosexual transmission may be comparable to or slightly lower than its effectiveness at preventing pregnancy     

COVID-19 and mental health: a longitudinal population study from Norway

European Journal of Epidemiology - Existing research has found adverse short-term effects of the COVID-19 pandemic on mental health, but longer-term effects have been less documented. Using newly...     

The potential impact of an HIV vaccine with limited protection on HIV incidence in Thailand: a modeling study

Background

The RV144 trial on the ALVAC/AIDSVAX candidate HIV vaccine, carried out in Thailand, showed short-lived protection against infection.

Methods

Using a deterministic compartmental model we explored the potential impact of this vaccine on heterosexual HIV transmission in Thailand. Both one-off vaccination strategies, as well as strategies with regular boosting, either annually or every two years, were explored. Both targeting the general adult population and prioritizing sex workers were modeled. The impact of risk compensation among high risk groups, as well as whether higher levels of safe sex in high risk groups could be an alternative to vaccination, was studied.

Results

One-off vaccination campaigns had only transient effects, and boosting appears to be a key component of successful vaccination campaigns. Intensive vaccination campaigns may reduce HIV incidence by up to 75% after 10 years of vaccination. Targeting only sex workers has a smaller impact but has a more favorable cost-benefit ratio. Risk compensation has the potential of undoing much of the benefits of a vaccination program and may even increase incidence. In contrast, higher levels of safe sex among sex workers would provide a viable alternative to vaccinating this group.

Discussion

The new vaccine holds promise for controlling HIV in Thailand and similar countries. In view of the short lived protection of the vaccine, regular boosting of immunity as well as avoidance of risk compensation are essential. Targeting sex workers would achieve the greatest reduction in incidence per vaccination and may be considered for expensive vaccines but its cost-effectiveness has to be compared to alternatives.     

HIV status and gender: a brief report from heterosexual couples in Thailand

Although the impact of HIV falls on both partners of a married couple, the burden of stress may not be necessarily shared evenly. The researchers in this study examined the relations among HIV status, gender, and depressive symptoms among 152 married or cohabitating couples living with HIV in the northern and northeastern regions of Thailand. Depressive symptoms were assessed using a 15-item depressive symptom screening test that was developed and used previously in Thailand. Among the 152 couples, 59% were couples in which both members were people living with HIV (seroconcordant; both people living with HIV couples), 28% had only female members with HIV (serodiscordant; females living with HIV couples), and 13% had only male members with HIV (serodiscordant; males living with HIV couples). The prevalence of depressive symptoms between seroconcordant and serodiscordant groups was similar. However, females living with HIV reported significantly higher levels of depressive symptoms, regardless of their partners' HIV status. Future prevention programs focusing on serodiscordant couples should be planned to target HIV risk, as well as emphasis on mental health, with a particular focus on women's increased susceptibility to negative mental health outcomes.     

Sex-specific trends in mortality for the aging population in Norway: a model with age, period, and cohort effects

During the last few decades, the citizens of most western countries have experienced an increased expectation of life. The rate of this change differs for males and females. We evaluated reasons for this pattern, using a Poisson model, with age, period, and cohort effects applied to vital statistics data from the Central Bureau of Statistics of Norway. The data comprised the total Norwegian population aged 45 to 104 years who died in the period from 1966 until 1986. Differential changes in life expectancy for the elderly are explained by differences in sex-specific cohort effects. We also observed an extra-Poisson variation, or overdispersion, in the distribution for females.     

Containing the spread of HIV infection: a world health priority

The World Health Organization (WHO) estimates that the world total of AIDS cases will reach 300,000 by the end of 1988 and 500,000 to 3 million over the next 5 years. AIDS is of special concern to developing countries with their limited, stressed health care systems and the other serious health problems of their populations. Also, AIDS usually strikes the young and productive adults that the economies of these countries can least afford to lose. The Surgeon General of the Public Health Service has challenged the United Nations to make the world's blood supply safe by 1991. Private and public sector leaders could come together, apply the technology and resources available in industrialized countries, and achieve a victory in this facet of the AIDS pandemic. The WHO's global strategy has led to the establishment of national AIDS committees in 151 countries and the preparation of 70 short-term (6-12 months) plans and 25 medium-term (3-5 years) plans for national AIDS control programs.     

Vitamin A serostatus and heterosexual transmission of HIV: case-control study in Tanzania and review of the evidence

Results from a randomized clinical trial suggested that vitamin A/beta-carotene supplementation to HIV-1-infected women during pregnancy and lactation may increase the risk of vertical transmission. Limited information is available on the potential role of vitamin A on heterosexual HIV transmission. This is a relevant question in many resource-limited settings where both vitamin A deficiency and HIV infection are highly prevalent. We conducted a case-control study (34 cases and 38 controls) nested within a cohort of HIV-negative women attending family planning clinics in Tanzania, to examine whether low serum concentrations at baseline were associated with the risk of seroconversion. There was not a significant association (OR = 2.14, 95% C I = 0.54, 8.45). In light of these and previous results, we conclude that there is not enough evidence yet to suggest a causal association between vitamin A and heterosexual transmission.     

Potential for spread of HIV in Japan]

Beginning 3 years ago, rapid spread of HIV was observed in Thailand with consequent serious problems in the public. HIV initially spread among i.v. drug abusers and then invaded prostitutes. Sero-surveillance estimates that there are 300,000 HIV positives in all of Thailand. Thai authorities warn that 4 million persons may be infected by the year 2000. In Japan, the cumulative number of HIV positives is reported as 453 excluding hemophiliac cases. However, the reported figures are assumed to be only a part of the actual figure. WHO estimates there may be 20,000 HIV positives in Japan. From the epidemiological surveillance, incidence of HIV positives even in the risk groups is extremely low in Japan. HIV positives in blood donors is merely 0.31 per 100,000. The question is whether AIDS will continue to be a less serious problem in Japan? Examination of blood or a voluntary basis may not tell the real situation of HIV positives in Japan. There is a real concern regarding HIV positives in female foreign visitors who made up 86 per cent of all female positives in Japan. These females are suspected to be professionals engaged in sex business in Japan. A hypothetical simulation indicates they may possibly infect 60,000 people per year. On the other hand, contact between Japanese travellers visiting Thailand and Thai prostitutes is also possible. Using the figure of 230,000 males visiting Thailand in 1990, hypothetical simulation revealed that 690 may become infected per year which is 1/50 of those calculated to be infected inside Japan.(ABSTRACT TRUNCATED AT 250 WORDS)     

HTLV-3 infection and AIDS: risk of spread by heterosexual contact

This article reviews current research evidence on the natural history, epidemiology, and clinical features of acquired immunodeficiency disease (AIDS) and presents guidelines for controlling the sexual transmission of human lymphotropic virus type III (HTLV-III) infection. The rapid spread of HTLV-III infection through homosexual communities in the US and Europe and its association with promiscuity initially obscured the fact that heterosexual transmission is also a significant risk factor for infection. Public health workers and epidemiologists are examining which sexual practices are most associated with the transmission of HTLV-III infection. Case-control studies in homosexuals have suggested that promiscuity, passive anal intercourse, and other sexual practices associated with rectal trauma and bleeding correlate with infection. Similar studies involving heterosexuals have not been conducted. However, the following guidelines have been proposed for couples where 1 partner has been found to be positive for HTLV-III antibodies: 1) sexual partners should be confined to established relationships; 2) anal intercourse should be avoided, even if the male uses a condom; 3) no oral contact with semen should occur; 4) if vaginal intercourse is practiced, the use of condom is essential; and 5) the only practices that are free from risk of infection are mutual masturbation and hand caresses. Since a high proportion of children of women with HTLV-III develop severe immunodeficiency, it is undesirable for women who are HTLV-III antibody positive to become pregnant. Furthermore, there is evidence that women who are HTLV-III antibody positive are more likely to develop AIDS if they become pregnant. A reliable method of permanent or reversible contraception is recommended for these women. Finally, men who are antibody positive should not donate sperm to a sperm bank.     

The carnitine-deprived newborn rabbit: a potential model to study carnitine deficiency

This report describes the novel development of an animal model for neonatal carnitine deficiency using the artificially fed newborn rabbit. Each litter was separated from the mother following the first colostrum feeding and divided into 2 groups, one of which was fed a purified rabbit formula that was essentially free of carnitine; the other received the same formula supplemented with L-carnitine (100 mg/l). At 9-13 d of age, rabbit pups receiving the carnitine-free formula had lower concentrations of total, free and acylcarnitine in plasma and urine, as well as lower total acid soluble carnitine concentrations in liver, muscle, heart and brown adipose tissue than those receiving the same formula supplemented with L-carnitine. Their plasma and tissue levels were also lower, but their urinary carnitine concentrations were higher than those in naturally-raised pups. The findings suggest that the described animal model may prove to be a useful tool for the investigation of certain aspects of neonatal carnitine deficiency.     

Masculinity and HIV disclosure among heterosexual South African men: implications for HIV/AIDS intervention

Relationships and constructions of masculinity are central to understanding the process of male HIV disclosure, which is an important step towards accessing HIV-related services. Data from in-depth interviews and focus-group discussions with 23 HIV-positive, self-identified heterosexual, Black South African men were used to explore the disclosure process and how this process was negotiated in the context of constructions of masculinity. Of these men, 20 had disclosed to one or more persons, with partners and siblings being the preferred confidants. Disclosure was dependent on the acceptance of HIV status, perceived support and healthy relationships with others, HIV counselling and participation in educational and training activities. Non-disclosure was explained as a result of stigma, fear of rejection, discrimination, a lack of healthy relationships with others and lack of access to suitable disclosure strategies. Negative perceptions of HIV and hegemonic conceptions of masculinity hindered men from disclosing and seeking health services. Many men, however, managed to renegotiate their masculine identities to become responsible, knowledgeable HIV-positive individuals, protecting their families and becoming community educators. Findings suggest the need to consider gendered, contextual, skills-building/income-generating and guided interventions to promote male HIV disclosure and service uptake.     

Masculinity and HIV disclosure among heterosexual South African men: implications for HIV/AIDS intervention

Relationships and constructions of masculinity are central to understanding the process of male HIV disclosure, which is an important step towards accessing HIV-related services. Data from in-depth interviews and focus-group discussions with 23 HIV-positive, self-identified heterosexual, Black South African men were used to explore the disclosure process and how this process was negotiated in the context of constructions of masculinity. Of these men, 20 had disclosed to one or more persons, with partners and siblings being the preferred confidants. Disclosure was dependent on the acceptance of HIV status, perceived support and healthy relationships with others, HIV counselling and participation in educational and training activities. Non-disclosure was explained as a result of stigma, fear of rejection, discrimination, a lack of healthy relationships with others and lack of access to suitable disclosure strategies. Negative perceptions of HIV and hegemonic conceptions of masculinity hindered men from disclosing and seeking health services. Many men, however, managed to renegotiate their masculine identities to become responsible, knowledgeable HIV-positive individuals, protecting their families and becoming community educators. Findings suggest the need to consider gendered, contextual, skills-building/income-generating and guided interventions to promote male HIV disclosure and service uptake.     

The impact of needle-exchange programs on the spread of HIV among injection drug users: A simulation study

Objective. To determine the impact of the implementation of a needle-exchange program (NEP) on the spread of human immunodeficiency virus (HIV) in an injection drug user (IDU) community. We conducted a Monte Carlo simulation study of a theoretical population of 10,000 IDUs. The population was followed monthly from 1984 to 2000. HIV was assumed to be transmitted only by needle sharing. The NEP was introduced in 1989 and evaluated over a period of 11 years. The impacts of the proportion of the population attending the NEP, the risk level of IDUs attending the NEP, the reduction in needle-sharing frequency, and the number of new needle-sharing partners acquired at the NEP on prevalence and incidence of HIV were determined. Increasing the proportion of the population who always attend the NEP and eliminating needle-sharing incidents among IDUs who always attended the NEP were the most effective ways of reducing the spread of HIV. Attracting high-risk users instead of lower risk users to the NEP also reduced the spread of HIV, but to a lesser extent. NEPs are effective at reducing the spread of HIV; even under the worst case scenario of low risk users more likely to attend the NEP, one additional partner per month as a result of attending the NEP, and poor NEP attendance, the estimated prevalence was still less than that from the scenario without an NEP. Under our model, NEPs were shown to reduce the spread of HIV significantly. Efforts should be focused on getting as many IDUs as possible to become regular NEP attenders and stop sharing needles rather than partially reducing the frequency of sharing by a larger number of IDUs.     

Psychological and behavioral factors unpredictive of disordered eating: a prospective study of the general adolescent population in Norway

OBJECTIVE: To investigate if cross-sectionally identified correlates of disordered eating among adolescents could also predict disordered eating prospectively over and beyond the initial level of disordered eating. METHOD: Two-wave longitudinal questionnaire study of a representative and nationwide sample of 7,751 Norwegian adolescents aged 12-19 at initial testing (t1). A 12-item version of the Eating Attitudes Test (EAT) was included. RESULTS: Forty percent of the girls and 25% of the boys with disordered eating at t1 also scored above the cut-off point 2 years later (t2). Initial disordered eating, gender, depressed mood, body dissatisfaction, unstable self-perceptions, perceived obesity, excessive exercise, and having idols with perfect bodies all predicted change in disordered eating. However, when the initial symptom load was controlled, these variables - except gender - only contributed marginally to the prediction of disordered eating. These negative results are in line with other longitudinal studies of changes in disordered eating in unselected adolescent populations. DISCUSSION: It cannot be established that psychological factors play a major etiological role in the development of disordered eating. The results are discussed with reference to a potential discontinuity between eating problems and eating disorders.