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.

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.

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.

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.