[Zidovudine plus didanosine in HIV infected asymptomatic patients previously treated with zidovudine]

OBJECTIVE

To evaluate if the combination of AZT/ddl offered any advantages in surrogate markers among HIV infected asymptomatic patients previously treated with AZT for at least six months.

METHODS

We used a prospective cohort of 269 asymptomatic HIV patients with CD4+ cell counts between 200 and 500 cells/microL. They were given didanosine (ddl 400 mg/d) in addition to AZT (500 mg/d) and had received AZT monotherapy for an average of 20 months. End points were progression to AIDS, death, or toxicity.

RESULTS

Median CD4+ cell count at the start of the combination therapy was 339 cells/microL which increased at three months to 451 and subsequently declined at 6, 12 and 18 months of followup (medians of 392, 360, 307 cells/microL respectively). Five patients progressed to AIDS, six developed toxicity (myelosuppression, hepatitis or pancreatitis) and 26 had minor side effects that required only dose reduction.

CONCLUSIONS

The addition of ddl to patients with prolonged ZDV monotherapy can be useful. CD4+ T cell counts showed a significant increase at 3 months with a gradual subsequent decline to below baseline at 18 months. Adverse effect of the drugs, although frequent, did not stop therapy in most patients.

Hepatitis B markers in men seeking human immunodeficiency virus antibody testing in Mexico City

OBJECTIVES

To estimate the prevalence and associated risk factors of hepatitis B virus (HBV) serologic markers in 1,377 men with high-risk sexual behavior attending a center for human immunodeficiency virus (HIV) detection in Mexico City.

METHODS

The study population consisted of all men who were tested for HIV from March to September, 1992. Study participants responded to a standardized questionnaire and provided a blood sample for serology.

RESULTS

A total of 1.9% of the population were hepatitis B surface antigen (HBsAg) carriers, and there was a significant difference in HBsAg prevalence between HIV-negative (0.8%) and HIV-positive individuals (7.9%). Sexual preference was associated with HBsAg prevalence; only 0.3% of men who had female sexual partners exclusively were HBsAg carriers, compared with 4.8% of men who had male sexual partners exclusively. Prevalence of antibodies to hepatitis B core antigen (anti-HBc) was 15.4%. However, men who reported only female partners had a 4.6% prevalence, whereas men who had only male partners had a 30.4% prevalence. Logistic regression analysis demonstrated an association of anti-HBc prevalence with age, marital status, sexual preference, seropositivity for HIV, and antibodies to herpes simplex virus type 2.

CONCLUSIONS

These data demonstrate that coinfection with HBV is common in the HIV-positive men studied. The highest prevalences of HBsAg and anti-HBc were observed among homosexual men. These results highlight the need to intensify safe-sex education campaigns and to promote hepatitis B vaccination especially among this population group.

[Seroprevalence of various viruses and sociodemographic characteristics of women seeking HIV screening]

OBJECTIVES

To study the seroprevalence of syphilis, herpes simplex-2, hepatitis B and HIV, and main sociodemographic characteristics and sexual behavior in women seeking testing for human immunodeficiency virus (HIV) in Mexico City.

METHODOLOGY

A self-applied questionnaire was used in 454 women; and a blood sample was taken for the detection of markers for syphilis, herpes simplex virus-2 (HSV-2)), antibodies against core and surface antigens for hepatitis B virus (HBV), and ELISA and Western blot for HIV.

RESULTS

Seroprevalences for antibodies against T. pallidum, HSV-2, HBV and HIV were 4.6%, 29.3%, 3.5% and 4.0%, respectively. Forty-six percent of the women were 20 to 29 years old; 70% reported complete junior high school or higher education level; 75% were sexually active; 56% reported at least one stable male sexual partner, 17% reported at least one occasional male sexual partner in the last three months, and 60% had had at least one sexual relation in the last three months; of these, only 18% (n = 82) reported the use of a condom as a preventive measure. Almost 30% of the HIV positive women had a history of blood transfusion, while less than 10% of the HIV negative women had received a transfusion. In addition, 10.6% said that one of their sexual partners was infected with HIV or had AIDS.

CONCLUSIONS

Risks of HIV/STD transmission for this group of self-selected women were linked to blood transfusion, low education and, most important, the risk from male sexual partners who were HIV seropositive. It is expected that these results will contribute to the improvement and development of strategies for the control and prevention of STD among this population group, as well as the general population in Mexico.

[Simplified CD4+ T-lymphocyte count in patients with HIV/AIDS in Mexico]

OBJECTIVE

To study the correlation between ALC and CD4 cell counts and to find alternative ways of counting CD4+ T-lymphocytes.

MATERIAL AND METHODS

The double positivity for CD3/CD4 antibodies was measured in 175 consecutive HIV-positive patients using flow cytometry; in these cases a difference was made between counting cells that were positive for both antibodies vs those that were positive only to CD4. ALC and CD4 counts were also compared among 500 subjects infected with HIV, using linear regression analysis and comparing the number of dissimilar cases for counts below 200 cells/microliters and ALC counts lower than 1 500 and 2000 cells/microliters.

RESULTS

In the 175 cases measured by the CD3/CD4 antibody combination the mean percent was 13.8% and for total CD4 cells 14.2% (p = NS); the mean difference was 0.4% and the median 0.2%. For the 500 patients the mean ALC was 1 700 cells/microliters and the mean CD4 count was 219 cells/microliters; the correlation coefficient was 0.59.

CONCLUSIONS

These data suggest a poor correlation of ALC and CD4 cell counts, thus it is impossible to predict CD4 on the basis of ALC. This is the reason why it is necessary to measure CD4 cells separately. The difference between measuring double positive CD3/CD4 cells vs only CD4 positive cells was not significant. Our data suggest that the use of a single CD4 antibody may cut costs and still produce clinically useful information.

[Sexually transmitted diseases and the HIV/AIDS epidemic]

Studies on sexually transmitted diseases (STD) during the previous years in Mexico are discussed. The information sources were: a) Surveys among commercial sex workers. Since 1990, 1,386 women have been studied in four federal states through structured questionnaires and laboratory tests. Prevalence of different STD's has been significant (syphilis (VDRL, FTA-abs) 23.7%; chlamydiosis (Ag IF) 12.9%; gonorrhea (Ag, ELISA) 11.5%; anti-HBs 11.0%; herpes 1,2 (IgM) 9.3%, HBsAg 5.7%. Frequency of HIV (ELISA, Western blot) has been low; 0.5%. In 1994, 662 women were studied in Mexico City, with different laboratory techniques for chlamydiosis and gonorrhea (culture), hepatitis B (anticore antibodies) and herpes (total antibodies) with the following results: syphilis 1.5-12%; chlamydiosis 10.8-11.7%; gonorrhea 0-5.9%; hepatitis B 0-7.1%; herpes 44.7-78%; and HIV 0-1.4%. b) Surveys among men with homosexual and bisexual practices. 325 subjects have been studied in three federal states using methods similar to those of the 1990 survey. Contrasting with results among women, HIV prevalence was found to be high; (18.8%), and considerable for other STD's: anti-HBsAg 28.6%, syphilis 34.9%, recent herpes 10.9%, HBsAg 5.0%, chlamydiosis (Ag, IF) 4.3%, herpes simplex 1,2 (Ag, IF) 4.7%, gonorrhea (Ag, ELISA) 2.8%. c) Patient clinical studies. The clinical interrelationship between different STD and HIV infection has been studied; clinical differences are described between patients with condylomata or syphilis depending on HIV serostatus. Implications of the interrelationship between different STD's and HIV infection for the prevention and control of these diseases are discussed.

[Prostitution and AIDS in the city of Mexico]

Since 1987 The National AIDS Council in Mexico (CONASIDA), has conducted research projects among female commercial sex workers (CSW), who are seen at the AIDS Information Centers. Through these studies, we have been able to find out how different issues influence commercial sex work in Mexico City. Since the beginning of our own studies in 1989, HIV prevalence in this particular group has remained low (0.04%-0.2%). Factors found to be associated with condom use were: educational level, not having children, more experience in sex work and younger age. Condom use was reported by 88% of the women; however, qualitative information and high STD prevalence rates suggest a much lower condom use. Mandatory HIV testing is not useful as a preventive measure among sex workers. Persuasive and structural interventions must be implemented in accordance with local and legal situations.

[The homosexual transmission of HIV/AIDS in Mexico]

OBJECTIVE

To analyze HIV homosexual transmission in Mexico, epidemic trends and biological and social risk factors.

METHODS

This analysis is based on 19,090 notifications of AIDS cases and on a review of two previous studies that include 3,029 behavioral interviews (together with HIV serological screening tests) carried out at the Information Center of the Mexican Council for Control and Prevention of AIDS (CONASIDA) (1988-89) and during a 1988 study in six Mexican cities. Cities were included because they were the larger in the country and/or because they were the larger in the country and/or because they were touristic places (Mexico City, Guadalajara, Monterrey, Acapulco, Tijuana and Merida). Logistic regressions were used to estimate the odds ratios for HIV seropositivity and for condom use.

RESULTS

Seventy-two percent of the total reported AIDS cases (19,090) up to June 30, 1994, were associated with male homosexual behaviors. In absolute numbers, cases under this category exhibited a rising trend until the end of 1993. HIV seroprevalence was 31% in 2,314 men with homosexual practices who attended "FLORA", the AIDS Information Center in Mexico, from January 1988 to June 30, 1989. The main predictive variables for seropositivity were exclusive homosexual behavior, more than 40 lifetime sexual partners, mixed sexual behavior (both insertive and receptive and intercourse), sex with a person with AIDS, history of syphilis, and anal or genital warts. In general, these risk factors (data from the Information Center) are similar to those found in the six Mexican cities study. There were significant differences in HIV prevalence among the high-risk city samples (the highest in Mexico City with 25% and the lowest in Monterrey with 2.4%). Reported condom use was very low in both studies: only 5% used a condom in all of their sexual relationships. A statistically significant protective effect for HIV infection was found only for those who reported using a condom in all sexual encounters. In the six cities study, city of residence was a strong predictor of condom use.

CONCLUSIONS

HIV homosexual transmission is steadily increasing; the recent decline in the percentage of homosexual cases is artificial because of the increment of cases under other categories. Men who report exclusive homosexual behavior have higher prevalence rates of infection than bisexual men. Individuals with insertive/receptive behavior (mixed) have the highest risk for HIV seropositivity, mainly because of sociological, rather than biological reasons. This difference in risks for HIV and condom use may be related to the selection of sexual partners from specific social networks. Condom use was demonstrated to be an effective method for preventing HIV seropositivity among those who always use condoms. However, it is alarming that only 5% of respondents reported condom use in all sexual encounters. Social and geographic differences in the cumulative numbers of cases, HIV prevalence, sexual practices and condom use must be taken into account in the planning of preventive programs.

[The health worker and counseling about HIV and AIDS]

By December 1993, more than 17,000 AIDS cases had been reported in Mexico and some estimates indicate approximately 100,000 individuals currently infected with HIV. From the patient's perspective, being HIV positive or having AIDS, places an enormous burden on psychosocial coping mechanisms. Thus, psychosocial support is required for all of these patients. This paper summarizes our educational intervention on counseling techniques and provides information of our demonstration project on the effectiveness of the educational intervention among 89 Mexican health care workers. Overall, these professionals showed improvement in their knowledge and goals of providing counseling. One of the more striking was the discovery of homophobic attitudes among them, particularly those with no previous experience in the care of HIV infected people. This exploratory study allowed us to identify research and educational needs of health care workers. The overwhelming number of estimated cases of HIV infections and the current trends of the epidemic reveal the necessity for training in medical counseling that over 73,000 physicians in Mexico will face in the immediate future.

[AIDS and human rights]

AIDS and human rights are closely related issues. This paper describes the relationship between AIDS and human rights, the impact and consequences of discrimination and the importance of the defense of human rights as a cornerstone strategy in AIDS prevention. Some general ethical aspects are addressed and two dilemmas which have been raised by the epidemic are discussed: the apparent conflict between individual and community rights and the reactions of intolerance and repression from those who claim that only through coercive strategies will the epidemic be brought under control. Specific problems in Mexico are described based on data collected at CONASIDA's Human Rights Department between 1992 and 1994. Finally some conclusions are stated emphasizing that, in the AIDS epidemic, the defense of human rights is the cornerstone of any public health strategy.

[Campaigns against AIDS in Mexico: the sounds of silence or a bridge over troubled waters?]

This paper analyzes the mass media campaigns developed by the Mexican Council for AIDS Control and Prevention (CONASIDA) from 1987 to 1994. This paper presents the lessons learned, a discussion of obstacles and mistakes, and the different evaluation methods which have been used in CONASIDA'S mass media communication strategies and their results. Knowing the opinion of some clue informants was considered relevant--taking into account that evaluations were made by and at CONASIDA--and seven in-depth interviews were conducted among intellectuals, non-governmental organizations (NGO) leaders and public opinion leaders. The importance of society's involvement in AIDS prevention is stated, and two examples of mass media campaigns developed by civil groups are commented. A section about the importance of research as a requisite to produce preventive messages is included, along with some examples. Finally, some conclusions are presented, useful to us, as well as others, in developing new educational campaigns.

[AIDS mortality in Mexico from 1983 to 1992. The trends and years of potential life lost]

OBJECTIVE

To describe trends in AIDS mortality in Mexico from 1983 to 1992, as well as years of potential life lost (YPLL) and years of potential productive life lost (YPPLL) due to AIDS.

MATERIAL AND METHODS

A retrospective review of databases available in Mexico that code mortality from AIDS was performed. Since AIDS was not coded specifically as a cause of death until 1988, for the period 1983-1987 the database of AIDS cases from the national AIDS registry provided by the Instituto Nacional de Diagnóstico y Referencia Epidemiológicos of the Ministry of Health was used. For the 1988-1992 period, a review of the mortality registry was provided by the Dirección General de Estadística, Informática y Evaluación of the Ministry of Health. To calculate YPLL and YPPLL we used the upper limit of expected life in Mexico for 1990 (70.79 years for men and 75.71 for women).

RESULTS

Through 1992, there have been 8,204 deaths attributable to AIDS in Mexico (86% were men) with a rate of 2.9 deaths/100,000. In 1992 AIDS was the 19th leading cause of death in the country. The most affected age groups are the 25-34 and 35-44 years-old (especially amongst men) in which AIDS has now displaced pulmonary tuberculosis, suicide and self-inflicted injuries, diabetes mellitus, cerebro-vascular disease and alcohol dependency syndrome as leading causes of death in men. Our data suggests that AIDS has caused, from 1983 through 1992, 247,045 YPLL in men and 48,703 in women as well as 206,211 YPPLL in men and 29,793 in women.

CONCLUSIONS

AIDS is at present one of the leading causes of death in Mexico. However, due to under-reporting, these estimates should be considered conservative and as lower-bound estimates. This data suggests that professionals are over-represented among AIDS cases, in comparison with the 1990 Population Census. This does not happen to be the case among women who are housewives.

[The prevention of sexually transmitted diseases and AIDS by the use of the condom]

This paper deals with the last literature and examines the most relevant studies of recent years related to condom effectiveness in preventing sexually transmitted diseases (STD), with experimental, epidemiological and seroconversion models. On the basis of these studies, it can be stated that the efficacy of condoms is close to 100 per cent when used correctly and consistently. Condom breakage has been reported in 0.5 per cent of vaginal intercourse and 3.6 to 10 per cent of anal intercourse. Most studies refer low failure rates due to manufacturing defects. Considering all constraints involved in masculine condom use and their implications for women, a female condom has been developed recently. It is not enough to give information or to make condoms available, if all the elements involved in the enhancement or failure of its use are not considered. Sexual education programs are the fundamental strategy in preventing STD and pregnancy.