HIV Transmission In Thailand Research Articles

History of the prevention of mother-to-child transmission of HIV in Thailand

Strategies for the prevention of mother-to-child transmission (PMTCT) of HIV have undergone considerable evolution based on scientific evidence, both at global and local levels. Because of the rapid expansion of the HIV epidemic among the heterosexual population, and the relatively advanced mother and child health infrastructure, Thailand has been the site of international study for more efficacious and cost-effective PMTCT regimens since mid-1990. The example of the Thai Red Cross Society in providing standard PMTCT care through public donations under the patronage of Her Royal Highness Princess Soamsawali is an example that non-governmental organisations in other countries can follow to accelerate access to standard PMTCT care. However, there are still many challenges before vertical transmission of HIV is completely eradicated.

Modeling of In-Utero and Intra-Partum Transmissions to Evaluate the Efficacy of Interventions for the Prevention of Perinatal HIV.

BackgroundAntiretroviral treatments decrease HIV mother-to-child transmission through pre/post exposure prophylaxis and reduction of maternal viral load. We modeled in-utero and intra-partum HIV transmissions to investigate the preventive role of various antiretroviral treatments interventions.MethodsWe analysed data from 3,759 women-infant pairs enrolled in 3 randomized clinical trials evaluating (1) zidovudine monotherapy, (2) zidovudine plus perinatal single-dose nevirapine or (3) zidovudine plus lopinavir/ritonavir for the prevention of mother-to-child transmission of HIV in Thailand. All infants were formula-fed. Non-linear mixed effect modeling was used to express the viral load evolution under antiretroviral treatments and the probability of transmission.ResultsMedian viral load was 4 log10 copies/mL (Interquartile range: 3.36–4.56) before antiretroviral treatments initiation. An Emax model described the viral load time-course during pregnancy. Half of the maximum effect of zidovudine (28% decrease) and lopinavir/ritonavir (72% decrease) were achieved after 98 and 12 days, respectively. Adjusted on viral load at baseline (Odds ratio = 1.50 [95% confidence interval: 1.34, 1.68] per log10 copies/mL increment), antiretroviral treatments duration (OR = 0.80 [0.75, 0.84] per week increment) but not the nature of antiretroviral treatments were associated with in-utero transmission. Adjusted on gestational age at delivery (<37 weeks, OR = 2.37 [1.37, 4.10]), baseline CD4 (Odds ratio = 0.79 [0.72, 0.88] per 100 cells/mm3 increment) and predicted viral load at delivery (OR = 1.47 [1.25, 1.64] per log10 copies/mL increment), single-dose nevirapine considerably reduced intra-partum transmission (OR = 0.32 [0.2, 0.51]).ConclusionThese models determined the respective contributions of various antiretroviral strategies on prevention of mother-to-child transmission. This can help predict the efficacy of new antiretroviral treatments and/or prevention of mother-to-child transmission strategies particularly for women with no or late antenatal care who are at high risk of transmitting HIV to their offspring.Trial RegistrationThis analysis is based on secondary data obtained from three clinical trials. ClinicalTrials.gov. NCT00386230, NCT00398684, NCT00409591.

Advancing HIV prevention science: the roads from Cape Town

Advancing HIV prevention science: the roads from Cape Town

Economic Evaluation of 3-Drug Antiretroviral Regimens for the Prevention of Mother-to-Child HIV Transmission in Thailand

The current program for prevention of mother-to-child HIV transmission in Thailand recommends a 2-drugs regimen for HIV-infected pregnant women with a CD4 count >200 cells/mm(3). This study assesses the value for money of 3 antiretroviral drugs compared with zidovudine (AZT)+single-dose nevirapine (sd-NVP). A decision tree was constructed to predict costs and outcomes using the governmental perspective for assessing cost-effectiveness of 3-drug regimens: (1) AZT, lamivudine, and efavirenz and (2) AZT, 3TC, and lopinavir/ritonavir, in comparison with the current protocol, AZT+sd-NVP. The 3-drug antiretroviral regimens yield lower costs and better health outcomes compared with AZT+sd-NVP. Although these 3-drug regimens offer higher program costs and health care costs for premature birth, they save money significantly in regard to pediatric HIV treatment and treatment costs for drug resistance in mothers. The 3-drug regimens are cost-saving interventions. The findings from this study were used to support a policy change in the national recommendation.

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.

Risk factors of preterm delivery in HIV‐infected pregnant women receiving zidovudine for the prevention of perinatal HIV

Several studies have shown that preterm delivery, a primary cause of perinatal mortality and morbidity, is more frequent in HIV-positive women. This study aimed to determine factors associated with prematurity in HIV-infected women and identify risks for which specific interventions could be targeted. Data were prospectively collected in a clinical trial assessing the efficacy of different zidovudine prophylaxis durations for the prevention of perinatal HIV transmission in Thailand. Characteristics associated with prematurity - delivery before 37 weeks--were assessed using univariate and multivariate logistic regression and were subsequently used to identify subgroups of women at risk. Among 979 women, independent prematurity risk factors were: viral load <3.5 or >4.5 log copies/mL; hemoglobin > 11.5 g/dL; weight gain <0.25 kg/week; and body mass index <20 kg/m2. These factors allowed us to define four subgroups with an expected probability of prematurity increasing from 3% to 30%. The two subgroups with the highest expected probability of prematurity were considered to be 'at risk' as opposed to the two lowest (odds ratio = 2.6, 95% confidence interval: 1.7-4.0) and the sensitivity and specificity of the prediction were 51% and 71%, respectively. In this study, four risk factors of preterm delivery were identified allowing the identification of subgroups at increasing risk of prematurity. Adequate nutrition and the provision of highly active antiretroviral therapy during pregnancy as recommended by the World Health Organization for the prevention of perinatal transmission for immunocompromised women in resource-constrained countries may reduce the risk of premature delivery.

Reduction in mother-to-child transmission of HIV in Thailand, 2001–2003: results from population-based surveillance in six provinces

In 2000, Thailand implemented a national program to prevent mother-to-child HIV transmission (PMTCT). To describe the effectiveness of the prevention of mother-to-child HIV transmission program in Thailand. A register of HIV-exposed children at birth was created with follow-up of infection status. The register included children born to HIV-infected women between 1 January 2001 and 31 December 2003 at 84 public health hospitals in six provinces of Thailand. The main outcome measure was HIV infection in children. A total of 2200 children born to HIV-infected mothers were registered. Of these mother-infant pairs, 2105 (95.7%) received some antiretroviral prophylaxis, including 1358 (61.7%) who received the complete short-course zidovudine regimen during pregnancy and labor for the mother and after birth for the infant, with or without other antiretrovirals. HIV infection outcome was determined for 1667 (75.8%) children, of whom 158 [9.5%, 95% confidence interval (CI), 8.1-11.0%] were infected. Transmission risk was 6.8% (95% CI 5.2-8.9%) among 761 mother-infant pairs that received the complete zidovudine regimen alone, and 3.9% (95% CI, 2.2-6.6%) among 361 mother-infant pairs that received the complete zidovudine regimen combined with other antiretrovirals, usually nevirapine. The overall transmission risk from this cohort, including all antiretroviral prophylaxis combinations, is estimated to be 10.2%. The Thai national PMTCT program is effective in reducing mother-to-child transmission risk from the historical risk of 18.9-24.2%. The addition of nevirapine to short-course zidovudine beginning in 2004 may further improve program effectiveness in Thailand.

Monitoring and evaluating the national program to prevent mother‐to‐child HIV transmission in Thailand

AbstractIn the first three years of Thailand's program, 99 percent of its public hospitals participated in the national monitoring system. Data are used to adjust national or local policies, and practices can be adjusted to improve the program.

National program for preventing mother-child HIV transmission in Thailand: successful implementation and lessons learnedSiripon Kanshana and R.J. Simonds

National program for preventing mother-child HIV transmission in Thailand: successful implementation and lessons learnedSiripon Kanshana and R.J. Simonds

HIV infection in young men in northern Thailand, 1991-1998: increasing role of injection drug use.

Epidemic HIV-1 infections were first recognized in Thailand in 1988 but increased dramatically in the 1990s primarily as a result of sexual transmission. The Ministry of Public Health instituted programs, including condom promotion during commercial sex, and health education to prevent HIV transmission. We assessed the HIV infection prevalence and risk behaviors among eight cohorts of 21-year-old randomly selected male military conscripts in northern Thailand between 1991 and 1998 to evaluate temporal trends in HIV infection and risk behavior. The prevalence of HIV was 11.4% to 11.9% in 1991 through 1993 and progressively fell to 2.4% in 1998. The men reported progressive decreases in commercial sex from 80% in 1991 to 38% in 1998, increases in condom use for commercial sex to greater than 95% in 1998, and decreases in lifetime history of a sexually transmitted infection from 42% in 1991 to 4.4% in 1997. There was an increasing proportion of men who reported a history of injecting illicit drugs, however, which involved 1.0% of the men in 1991 but 4.2% in 1997. The population attributable risk of drug use for HIV infection increased in recent years; the proportion of HIV-positive men with a history of drug use increased from 1.0% in 1991 to 25.8% in 1998. The public health program to prevent the sexual transmission of HIV in Thailand continues to be highly successful. Nevertheless, injection drug use has emerged as an important risk behavior and is maintaining endemic HIV transmission in Thailand.

Short Anti-HIV Treatment Okay for Infant If Mother Receives Standard Regimen

A randomized trial involving 1437 HIV-infected women was conducted to determine whether the standard regimen of zidovudine could be shortened without increasing the risk of mother-to-child HIV transmission in Thailand. Participants were randomly assigned to four treatment groups: the first group consisted of women assigned to the standard regimen; the second group tested abbreviated regimens for both mother and child; the third regimen called for the standard treatment for the mother and the shortened treatment for the child; and in the fourth only the mothers treatment was shortened. Overall results showed that HIV transmission was significantly higher when both mother and child received shortened treatment. HIV transmission rates in the second group did not differ significantly with the group receiving the standard regimen. When both mothers and infants receive abbreviated zidovudine treatment however the transmission rate is more than double the rate for mother-infant pairs receiving the standard regimen (11% vs. 4%). Hence the study provides an evidence that pregnant women should be given the long regimen whenever possible.

Limited understanding of mother-to-child transmission of HIV in Thailand

Limited understanding of mother-to-child transmission of HIV in Thailand

HIV incidence rates among drug users in northern Thailand, 1993–7

Drug use is a major mode of HIV transmission in Thailand. This study determined HIV incidence rates among drug users in a regional drug treatment centre in northern Thailand. A retrospective cohort of repeatedly-hospitalized drug users between 1993 and 1997 was formed and HIV incidence rates were calculated. The overall incidence was 11.44 per 100 person-years of observation. Gender, age, religion, ethnicity, education, employment, income, reasons for drug use, type of drugs, mode of use, spending on drugs, and referral for treatment are associated with HIV incidence. However, there are no associations between HIV incidence and history of treatment and mode of discharge from the centre. This implies that current treatment modality has no impact on HIV infection risk and other therapeutic approaches should be explored.

Prevention of mother-to-child transmission of HIV in Thailand: physicians' attitudes on zidovudine use, pregnancy termination, and willingness to provide care.

We administered a survey to Thai physicians, using regular mail, on their attitudes and practices regarding zidovudine (ZDV) use and pregnancy termination in HIV-infected pregnant women. We surveyed their willingness to care for these patients as well. In 1997, 79.5% of 480 respondents reported that they did not routinely use perinatal ZDV prophylaxis. Predictors of failure to use ZDV found to be significant in our logistic regression model included practice outside of Bangkok (odds ratio [OR] = 2.0), belief that ZDV is not cost effective (OR = 2.5), unfamiliarity with AIDS Clinical Trials Group (ACTG) 076 results (OR = 2.5), and failure to screen for HIV routinely (OR = 4.9). Elective abortion for HIV-infected women was advocated by 45.3% of respondents. Factors associated in multivariable analysis with this preference included specialty training in obstetrics/gynecology (OR = 1.8), practice inside Bangkok (OR = 2.0), male gender (OR = 1.9), and treatment of < or =2 HIV-infected patients yearly (OR = 1.8). A significant proportion of respondents described themselves as unwilling to perform pelvic examinations (19.2%), vaginal deliveries (30.7%), or cesarean deliveries (39.5%) on women who were known to be infected with HIV. We conclude that many Thai obstetric providers are reluctant to care for HIV-infected women, do not routinely use perinatal ZDV prophylaxis, and prefer to terminate pregnancies among HIV-infected patients. Physician education concerning the value of HIV screening and antiretroviral therapy in HIV-infected pregnant women is needed urgently in Thailand.

Injection use as a risk factor for HIV transmission in Thailand

Injection use as a risk factor for HIV transmission in Thailand

Modelling the female-to-male per-act HIV transmission probability in an emerging epidemic in Asia.

The per-sexual-act probability of transmission of the human immunodeficiency virus type 1 (HIV) from an infected person to a susceptible sex partner can be determined from a simple model if the number of contacts each study participant has with infected partners is known. The unusual epidemiologic situation in the emerging HIV epidemic in Thailand allowed this quantity to be estimated from a cross-sectional study of young men conscripted into the Thai military in 1991. Although the simple model does not fit the data, an errors-in-variables approach provides a model with adequate fit. Other sources of lack of fit, including heterogeneity of the transmission probability, are discussed. With adjustment for measurement error, the per-act probability is estimated to be 0.056, an order of magnitude higher than similar estimates in North America. Because data indicate that recently infected persons may be more infectious, and because extensive HIV transmission in Thailand began in 1988, this difference may be due, in part, to a higher proportion of recently infected individuals in the emerging Thai epidemic from 1988 to 1991.

Knowledge and meaning: The AIDS education campaign in rural Northeast Thailand

Nearly 80% of Thailand's population live in the rural sector. To date, these villages have been subject to top-down dissemination of HIV/AIDS education information via the mass media and bureaucratic networks. This report details an ethnographic enquiry into the impact education campaigns are having in one village in Northeast Thailand. It is found that AIDS information is primarily integrated with local conceptions of sexual behaviour and commercial sex. By the early 1990s, heterosexual behaviour is a major mode of HIV transmission in Thailand. Local and international media discourse focuses on the commercial sex industry in describing the spread of the virus. However, the lack of detailed research of sexual practices in Thailand makes accurate projections of HIV transmission difficult and allows unsubstantiated claims to be made concerning typical Thai sexual behaviour. This paper explores the local context in which these practices are found and discusses the meanings villages attached to HIV/AIDS information. Knowledge levels and behaviour change are assessed and it is argued that community based imperatives are essential for effective future campaigning.

Behavioral and sociodemographic risks for frequent visits to commercial sex workers among northern Thai men

The transmission of HIV-1 in Thailand has recently been attributed to exposure to infected commercial sex workers (CSW). We sought to identify risk factors for patterns of CSW visits among northern Thai men. Retrospective recall of lifetime and recent CSW visits and associated risk factors were obtained by interview. Two military bases in northern Thailand. We enrolled two cohorts (n = 2417) of young men, aged 19-23 years, who were conscripted into the Royal Thai Army and Air Force from six provinces in northern Thailand in May and November 1991. Frequency of self-reported lifetime and recent sex with CSW. Multivariate results showed that lower socioeconomic status, early first intercourse and substance-use factors (alcohol, marijuana, other drugs, and smoking) associated with lifetime and recent sex with CSW. Sexual intercourse with other female partners, lower price paid at last CSW visit and frequency of condom use with CSW did not differentiate frequent from infrequent CSW visitors. Limits in the frequency of sex with CSW, improved condom practices and reduction of drinking prior to CSW visits would all appear to provide substantial protection from exposure to HIV-1 in this setting.