Intrapartum and neonatal zidovudine treatment in reduction of perinatal HIV-1 transmission in Bangkok.

OBJECTIVE: To evaluate the efficacy of zidovudine (ZDV) administered during labor and to the infants in the first 6 weeks of life in reduction of perinatal HIV-1 transmission. DESIGN: Open label clinical trial. SITE: King Chulalongkorn Memorial Hospital, Bangkok, Thailand. MATERIAL AND METHOD: One hundred asymptomatic, antiretroviral naive HIV-1 infected pregnant women who had either late or no prenatal care were recruited from the obstetric service of King Chulalongkorn Memorial Hospital, Bangkok, Thailand. They were given ZDV 300 mg orally every 3 hours during the intrapartum period until delivery. ZDV syrup 2 mg/kg orally every 6 hours were given to the infants immediately after birth for 6 weeks. Breast feeding was not allowed. Infant's blood for HIV-1 PCR test was obtained at age 1 day, and 1, 3 and 6 months. HIV-antibody test was determined at age 18 months. Infants with at least one positive HIV-1 PCR test performed at or after 1 month of age or positive HIV-antibody test at age 18 months were classified as HIV-1 infected infants. RESULTS: There were 100 healthy infants delivered without complication. Fourteen infants were excluded due to; 13 lost to follow-up and 1 drug intolerance. Of the remaining 86 infants who were followed-up, 27 infants (31.4%) did not receive intrapartum ZDV treatment and 9 infants were HIV-1 infected. The perinatal transmission rate was 10.5 per cent, (95% CI 3.9, 17.1). CONCLUSION: The result of this study suggests that intrapartum oral ZDV treatment in asymptomatic HIV-1 infected mothers together with ZDV treatment in the neonates for 6 weeks can reduce the rate of perinatal HIV-1 transmission. This regimen may be an alternative treatment for prevention of HIV-1 infection in infants born to HIV-1 seropositive mothers who have had either late or no prenatal care.

Update on HIV/AIDS in Thailand.

Thailand experienced its first case of AIDS in 1984. Approximately 800,000 Thais were infected with HIV in 1995 and 1 million Thais became infected by the year 2000. There have been 5 major epidemic waves: among male homosexuals (started 1984-5), intravenous drug users (started 1988), female commercial sex workers (started 1989), male clients (started 1990), and housewives and the newborn (started 1991). Approximately 96 per cent of HIV-1 infected Thais carried recombinant subtype A/E, the rest carried B'. In a male seroconvertors cohort of 235 cases, median time to show CD4 <200 cells/microL was 6.8 years. Five years survival was significantly lower than that of the other subtype B seroconvertors study, i.e., 82 per cent compared to 90 per cent. Interestingly, 13.5 per cent of seronegative Thais showed homozygous SDF1-3'A polymorphism, which suggests that approximately one-tenth of Thais may become long-term non-progressors after HIV-1 infection. Primary HIV infection syndrome is rare among Thai patients (1.1%). In contrast, it was 50-90 per cent in Western cohorts. In early symptomatic patients, one-third developed pruritic pappular eruptions (PPEs). In advanced stage, disseminated tuberculosis, Pneumocystis carinii pneumonia (PCP), cryptococcosis, and esophageal candidiasis are commonly found. In Northern Thailand, however, Penicillium marneffei infection or penicillosis is more common than cryptococcosis. The recent understanding of HIV pathogenesis suggests that HIV eradication is unlikely to be achievable with current strategies. Several National HIV treatment guidelines including the Thai guideline have been recommended treatment with triple antiretroviral regimen when patients become symptomatics or CD4+ <200. Current development of antiretroviral therapy which includes new agents, new formulas, and pharmacokinetic enhancements, is directed to better potency, higher genetic resistant barrier, less pill burden, and once a day dosing. These will ultimately improve the adherence and the long-term effectiveness of antiretroviral treatment. In reality, however, although the cost of triple regimen is dramatically declining, many patients still can not afford it. Primary prophylaxis and early diagnosis and treatment of opportunistic infection should be considered in patients with CD4+ <200 cells/microL. Modified short course ZDV studies and donation campaigns for preventing mother-to-child transmission, clinical trials to investigate the best use of expensive anti HIV medications in a poor resource setting have been or are being conducted. Nine phase I/II HIV-1 vaccine trial protocols have been or are being tested. A phase III trial of gp120 subtype B/E (AIDSVAX, VaxGen) was started in 1999, a total of 2,500 volunteers will be enrolled, and interim analysis is planned for August 2002. Thai investigators are also participating in pre-clinical development of recombinant BCG and DNA vaccines. Multidisciplinary and multi-level approaches, both by the government and private sectors, have had a positive impact on the HIV epidemic as shown by the declining seroprevalence of HIV infection in Thai male conscripts, and of major sexually transmitted diseases in men. Nevertheless, more effort at the grass roots level is needed to ensure further success and sustainability of the control of the HIV epidemic in Thailand.

Short course zidovudine maternal treatment in HIV-1 vertical transmission: randomized controlled multicenter trial.

A multicenter randomized, double blind, placebo-controlled clinical trial was conducted to evaluate the effectiveness of a short course of oral zidovudine (ZDV) treatment in HIV-1 infected pregnant women, starting at 38 weeks of gestation plus ZDV infusion during labor until delivery, to reduce HIV-1 vertical transmission in non-breast fed infants. One hundred and eighty two asymptomatic antiretroviral naïve HIV-1 infected pregnant women were enrolled. Each patient was randomly allocated into either the ZDV or placebo group. The ZDV group received 250 mg ZDV orally twice a day initiated at 38 weeks' gestation until the onset of labor. During the intrapartum period, ZDV infusion at the rate of 2 mg/kg was administered within the first hour and then continuously infused at the rate of 1 mg/kg/h until delivery. The placebo group received an identical capsule during pregnancy and normal saline infusion during labor until delivery. HIV-1 transmission was documented by nested polymerase chain reaction in infants at birth and at 1, 3 and, 6 months of age. The estimated HIV-1 vertical transmission rate was 14.9 per cent (95% CI = 11.1 to 18.7) and 16.3 per cent (95% CI = 12.3 to 20.9) in ZDV and placebo group, respectively (p > 0.05). The short course ZDV in antiretroviral naïve pregnant women initiated at 38 weeks' gestation plus intrapartum ZDV infusion without treatment in the infants was not effective to prevent HIV-1 vertical transmission.

Intrapartum zidovudine infusion alone failed to reduce both maternal HIV-1 viral load and HIV-1 infection in infant.

A pilot clinical trial to assess the efficacy of intrapartum zidovudine (ZDV) infusion alone in the reduction of maternal viral load and its potential role in preventing vertical transmission of HIV-1. Twenty six, asymptomatic antiretroviral naïve HIV-1 infected pregnant women who had no prior antenatal care and were in labor were enrolled. Each patient received ZDV infusion at the rate of 2 mg/kg within the first hour. ZDV was then continuously infused at 1 mg/kg/h until delivery. Maternal plasma HIV-1 RNA prior to the commencement of ZDV infusion and within an hour after delivery were measured. HIV-1 transmission was documented by nested polymerase chain reaction in infants at six months of age. Median maternal plasma HIV-1 RNA prior to the ZDV infusion and after delivery was 29,401 and 32,555 copies/ml respectively, (p>0.05). The estimated HIV-1 transmission rate was 19.2 per cent (95% CI = 4-34). This result suggested that in asymptomatic HIV-1 infected pregnant women who were antiretroviral naïve and had no prior antenatal care, intrapartum ZDV infusion alone failed to reduce maternal HIV-1 viremia and the transmission rate of HIV-1.

Trials in developing countries.

Good clinical trials can be carried out in the developing countries but ethical issues concerning the trials are frequently brought up for international debate. The concern has its own merit but can be amended if investigators (local and international) pay serious attention to these criticisms and work out the way that will most benefit the trial participants. Although scientific progress is important, it must come after the rights, the safety and the benefit of the patients. Frequently, the ethical standard is delicately balanced, depending on who looks at it and from what angles they look. Critics, investigators, volunteers, sponsors and regulatory agencies have their own mandates, expectations and limitations, and thus they need to keep an open line of communication in order to benefit all parties involved.

The risk of occupational HIV exposure among Thai healthcare workers.

To analyze the incidence of occupational exposure to HIV in a large group of healthcare workers at the 2 Thai Red Cross hospitals, prospectively collected during a seven-year period in order to find out the causes and circumstances that prone to exposure, the interventions that may minimize the exposure and the consequences of the accidents. The first 200 incident reports from 198 hospital workers of the Thai Red Cross Society who had occupational exposure to HIV-infected blood and body fluids during 1991-1997 were analyzed. We analyzed the demographic data, the timing and place of exposure, the nature and cause of exposure, HIV status at baseline and at follow-up at 3, 6 and 12 months as well as the received antiretroviral prophylaxis. All of the 198 HCW had negative anti-HIV at baseline and remained negative throughout the one-year follow-up although only 55% submitted the results of their anti-HIV testing at 6 months. However, none claimed for work-related life insurance against HIV during those 7 years indicating that nosocomial rate of transmission is less than 1 in 200 or less than 0.5%. Analysis of the incidents indicated that the risk group was the 20-40 years old nursing personnel who worked in the medical wards during the regular working hours. The procedures that were responsible for most of the injuries were venepuncture, intravenous access, injection and waste collection. Most of the injuries could be prevented if the work place safety guidelines were strictly followed and if personnel were more careful at work. The results can be used to implement more effective preventive measures for hospitals in Thailand. Postexposure management at the Thai Red Cross hospitals conformed with the international guidelines. However, only 78% of those who should receive postexposure prophylaxis were recommended for treatment and only 69% of those recommended actually took the treatment. This emphasizes the need to educate clinicians involved in postexposure care as well as to ensure them and the injured subjects about the safety of the antiretroviral prophylaxis.

International clinical trials of HIV vaccines: I. Phase I trial of an HIV-1 synthetic peptide vaccine in Bangkok, Thailand.

A randomized, double blind, placebo controlled Phase I trial of a prototype human immunodeficiency virus type 1 (HIV-1) synthetic peptide vaccine was conducted in Bangkok, Thailand, to evaluate the safety and immunogenicity of the vaccine in a population of healthy adults at low risk for HIV infection, and to establish essential infrastructure for future HIV vaccine trials in Thailand. Thirty volunteers (25 males; 5 females) were recruited and randomized into 3 groups, receiving 3 intramuscular injections of either 100 micrograms vaccine (N = 12) or 500 micrograms vaccine (N = 12) or alum placebo (N = 6) on weeks 0, 4 and 25. The vaccine was well tolerated without any serious adverse effects. HIV-1 specific ELISA responses were detected in 20/24 subjects who received the vaccine, with V3 binding antibody titers ranging from 1:69 to 1:5,041. HIV-1 (MN) specific neutralizing antibody was detected in 19/20 of subjects with detectable HIV-1 specific binding antibody. Neutralization titers ranged from 1:14 to 1:1,294, which were less than titers observed in HIV-infected subjects. The results of this study indicate that the vaccine was well tolerated, and that the vaccine stimulated anti-HIV humoral immune responses in Thai subjects. The successful undertaking of this first HIV vaccine trial conducted in Thailand provided important preparatory information surrounding volunteer recruitment and motivations, and paves the way for future trials of HIV vaccines in Thailand.

Standardization of methacholine inhalation challenge by a reservoir method.

Standardization of methacholine inhalation challenge (MIC) by a reservoir method was performed at Respiratory Unit, Chulalongkorn Hospital. One hundred subjects, including 20 non-smoking healthy subjects, 20 patients with isolated chronic cough, 20 patients with isolated allergic rhinitis, 20 patients with stable chronic obstructive bronchitis, and 20 patients with mild bronchial asthma, were scheduled to perform the test. The aerosolized methacholine was produced by an atomized nebulizer of the Provocation test I (Pari-Starnberg) and the aerosol was kept in a reservoir bag. It was inhaled by each subject via a slow vital capacity. Increasing concentrations of methacholine (0, 0.5, 1, 5, 10, and 25 mg/ml were used. None of the healthy subjects had increased bronchial hyperresponsiveness (BHR). Sixty percent of patients with chronic cough, 60% of patients with allergic rhinitis, 95% of patients with chronic obstructive bronchitis, and 100% of patients with asthma were found to be positive in the MIC tests. No serious effect from methacholine during and after the tests was found. It was concluded that MIC can be easily performed by a reservoir with reproducible results to demonstrate BHR.

Comparison of the sensitivity of various anti-HIV tests in early seroconversion sera.

Paired sera from 4 patients with proven HIV infection whose initial specimens obtained 14-51 days earlier were indeterminate were simultaneously retested with 7 screening anti-HIV test kits and the immunoblot assay. The study aimed to evaluate the sensitivity of various new and old anti-HIV screening tests. The test kits evaluated were 4 ELISA test kits from Wellcome (Wellcozyme), Organon (Vironostika anti-HTLV-III), Pasteur (Rapid Elavia) and Diagnostic Biotechnology (DB, HIV-1 ELISA), 2 rapid tests based on microfiltration enzyme immunoassay procedure from Rapport (SUDS) and Disease Detection International (SeroCard), and 1 particle agglutination (PA) test (Serodia-HIV). Immunoblot strips from Diagnostic Biotechnology (HIV-1 Western blot) were used to confirm the HIV infection in these serum specimens. Out of the 4 initial serum specimens tested, all were positive by PA, 2 by SUDS, Wellcome and Pasteur, 1 by SeroCard and DB, and none by Organon. When tested by immunoblot, 1 was negative (i.e., completely without any bands) whereas 3 were indeterminate (i.e., 1 with very weak band for p18, 1 with weak band for p24, 1 with very weak band for gp160. All repeat specimens obtained 14-51 days later (mean 32.5 +/- 16 days) were positive by all screening tests as well as immunoblot. Therefore, with these 4 early seroconversion sera, the sensitivity of the PA was 100%, that of SUDS, Wellcome and pasteur was 50%, of that SeroCard and DB was 25%, and Organon, 0%. None of these sera was considered positive by immunoblot.

Serum antibodies to HTLV-I in Thai patients with chronic progressive myelopathy, multiple sclerosis, myopathy and in HIV-seropositive intravenous drug abusers.

Antibodies to HTLV-I were assayed in sera of 9 patients with progressive myelopathy, 11 with multiple sclerosis, 5 with myopathy and in 10 HIV-seropositive intravenous heroin abusers. Clinical features in 9 cases with progressive myelopathy were not different from those previously described in tropical spastic paraparesis associated with HTLV-I infection. No detectable HTLV-1 antibody was found in the sera of any of the 35 patients studied.

Enhanced antibody response to rabies virus in patients with neurologic complications following brain tissue-derived rabies vaccination.

Sera from 26 patients with major neurologic complications, 19 patients with minor complications and 23 patients with no complications induced by Semple rabies vaccine were assayed for neutralizing antibody to rabies virus. Seroconversion to the protective level (greater than or equal to 0.5 IU/ml) was found in 21 of 22 patients (95%) with major complications, and in 7 of 19 (37%) with minor complications, occurring during the first 14 days of vaccination. This was in contrast to 42% (5/12) seroconversion in uncomplicated recipients after 14 daily injections. After initiation of dexamethasone treatment, 13 of 18 patients with major complications showed a diminution in their rabies antibody levels on day 4 or 7.

Humoral and cell-mediated immune responses to various economical regimens of purified Vero cell rabies vaccine.

Purified Vero cell rabies vaccine (PVRV) is a new effective but inexpensive tissue culture rabies vaccine for human use. We investigated if the cost of immunization with PVRV could be further reduced by intradermal immunization. Fifty-eight subjects with low-risk exposure to rabies were randomized into 4 groups to receive full-dose (0.5 ml) intramuscular injection of PVRV on days 0, 3, 7, 14 and 28 or 4, 2 or 1 intradermal injections of PVRV (0.1 ml) on days 0, 3, and 7, followed by another intradermal injection on day 28. Neutralizing antibodies and specific cell-mediated response (CMIR) were sequentially followed up to day 36. The antibody levels in the intradermal groups increased with the number of injection sites and the levels achieved by the 2-site i.d. regimen were not significantly different from those obtained by the full-dose i.m. even though only 1/3 of the amount of PVRV was used. Specific CMIR occurred 1 week sooner in the 2 and 4-site i.d. regimens than the full-dose i.m. We therefore recommended that our 2-site i.d. regimen of PVRV should be further tested with a view to substituting it for the more expensive full-dose i.m. regimen in order to further reduce the cost of rabies prophylaxis particularly in the developing countries.

Anti-HIV positivity in Thailand: the usefulness of another ELISA test kit and Western blot as confirmatory tests.

Sera from 47 individuals repeatedly reactive in one screening ELISA system (designated as ELISA-A) for antibodies against human immunodeficiency virus (HIV) were evaluated by a second ELISA system (designated as ELISA-B) as well as by the Western blot technique. Both ELISA systems and the Western blot were positive in all of the 14 patients with clinical diagnoses of AIDS and AIDS-related persistent generalized lymphadenopathy (PGL). Of the 7 asymptomatic gays whose sera were repeatedly reactive in ELISA-A, 5 were also reactive in ELISA-B and these were the ones with positive Western blot tests. Eight and 17 ELISA-A reactive individuals were uncovered during a survey of 2,699 female prostitutes and 15,210 potential workers for Saudi Arabia respectively. All of these 25 individuals were ELISA-B and Western blot negative, an indication of false-positive reactivity with ELISA-A. Our studies indicate that the prevalence of HIV infection among the general Thai population is still low, and that the specificity of two ELISA test kits for anti-HIV may differ considerably. We concluded that evaluation of test kits should include studies in tropical countries where ecological conditions, climate and background endemic disease patterns are different than in the countries producing the diagnostic systems. Such studies are needed to identify the most sensitive and specific kits for worldwide application. We did discover that concordant positivity of two different ELISA test kits served as a reliable and inexpensive confirmatory test for anti-HIV.

Effect of inosiplex on the humoral and cell-mediated immune responses to intradermal human diploid cell rabies vaccine.

Antigen-stimulated lymphocyte transformation was studied in recipients of intradermal human diploid cell rabies vaccine (HDCV). HDCV was administered intradermally at 8 different anatomical sites, 0.1 ml each, on day 0; followed by another 4-site injection on day 7. Rabies antigen-stimulated in vitro proliferative response was evident as early as 7 days after starting immunization. It reached a peak on day 14 and had declined by day 28. The cellular proliferative response preceded and roughly correlated with the antirabies antibody response. Simultaneous administration of inosiplex, an antiviral and immunopotentiating drug, during the first 10 days of intradermal HDCV immunization did not result in heightened antibody titres or cell-mediated immune response to the vaccine. The number of T cells and the lymphocyte proliferative response to phytohaemagglutinin in inosiplex-treated vaccinees were similarly not significantly different from untreated controls. Our results confirm other previous findings that a specific cell-mediated immune response can be consistently and rapidly induced by an intradermal regimen of HDCV immunization. The addition of inosiplex to this regimen did not enhance the humoral or cell-mediated immune responses to the vaccine. The apparent lack of immunostimulating effect of inosiplex in this setting may be the result of several factors such as the immunization schedule and the immunologic parameters examined.

Cell-mediated immune response following intracutaneous immunisation with human diploid cell rabies vaccine.

Specific cell-mediated immune response (CMIR) against rabies antigens was studied in recipients of two regimens of human diploid cell rabies vaccine (HDCV) using the antigen-stimulated lymphocyte transformation test (LTT) as a measure of CMIR. Reconstituted HDCV could be conveniently used as the in vitro stimulating antigen and the response was antigen-dependent. Conventional intramuscular immunization with full-dose HDCV resulted in positive LTT as early as 14 days after starting immunisation, and peaked on day 28. Intracutaneous immunisation with 0.1 ml of HDCV at four sites on days 0, 3 and 7 was a more efficient means of inducing specific lymphocyte response. Specific CMIR was evident as early as seven days and became maximal on day 14. In addition to the more rapid induction of specific CMIR, our intracutaneous regimen also resulted in a brisker and higher antibody response than the intramuscular regimen. The peak antibody level of the intracutaneous regimen was reached on day 14 whereas that of the intramuscular regimen was reached on day 28 and the geometric mean antibody titre on day 14 of the intracutaneous route was significantly higher than that of the intramuscular regimen. We therefore conclude that our closely spaced intracutaneous immunisation with HDCV was effective both in the induction of specific antibodies and the cell-mediated immune response.

A report of three cases of AIDS in Thailand.

Acquired immune deficiency syndrome (AIDS) has been rarely reported as occurring primarily in Asia. We report here on first three cases of AIDS diagnosed at Chulalongkorn Hospital Medical School. One case was an American who had been in Thailand for two years; the other two were Thai. The American and one of the Thai patients were male homosexuals but they had no connection with one another. The latter Thai male homosexual had sexual contact with a German man who showed no evidence of the disease. The other Thai patients was the mistress of the male Thai patient, which underlies the importance of heterosexual transmission of the disease. The two male patients had opportunistic infections whereas the female patient had only generalised lymphadenopathy (Pre-AIDS). Delayed type hypersensitivity response, T-cell subsets enumeration and the in vitro T-cell mitogen response served as diagnostic tools when combined with the clinical history. The diagnosis was made even before the results of tests to determine the presence of antibodies to HTLV-III were known. The presence of anti-HTLV-III simply confirmed our diagnosis.