Repeated exposure to an MF-59 adjuvanted quadrivalent subunit influenza vaccine (aQIV) in children: Results of two revaccination studies.

BACKGROUND: Pediatric adjuvanted seasonal influenza vaccines induce higher immune responses and have the potential to confer better protection against influenza among young vaccine-naïve children. Limited data describe benefits and risks of repeated administration of adjuvanted influenza vaccines in children. Two revaccination studies assess the safety and immunogenicity of repeated exposure to an MF59-adjuvanted quadrivalent influenza vaccine (aQIV; Fluad®) compared to routine non-adjuvanted quadrivalent influenza vaccine (QIV). METHODS: Children previously enrolled in the parent study, who received vaccination with aQIV or nonadjuvanted influenza vaccine (TIV or QIV), were recruited in Season 1 (n = 607) or Season 2 (n = 1601) of the extension trials. Season 1 participants remained in their original randomization groups (aQIV-aQIV or TIV-QIV); Season 2 subjects were re-randomized to either vaccine, resulting in four groups (aQIV-aQIV, aQIV-QIV, QIV-aQIV, or QIV-QIV). All subjects received a single-dose vaccination. Blood samples were taken for immunogenicity assessment prior to vaccination and 21 and 180 days after vaccination. Reactogenicity (Days 1-7) and safety were assessed in all subjects. RESULTS: Hemagglutination inhibition (HI) geometric mean titer (GMT) ratios demonstrated superiority of aQIV revaccination over QIV revaccination for all strains in Season 1 and for A/H1N1, B/Yamagata, and B/Victoria in Season 2. Higher HI titers against heterologous influenza strains were observed after aQIV vaccination during both seasons. Mild to moderate severity and short duration reactogenicity was more common in the aQIV than QIV groups, but the overall safety profiles were similar to the parent study. CONCLUSION: The safety and immunogenicity results from this study demonstrate benefit of aQIV for both priming and revaccination of children aged 12 months to 7 years.

Integrated systems approach defines the antiviral pathways conferring protection by the RV144 HIV vaccine.

The RV144 vaccine trial showed reduced risk of HIV-1 acquisition by 31.2%, although mechanisms that led to protection remain poorly understood. Here we identify transcriptional correlates for reduced HIV-1 acquisition after vaccination. We assess the transcriptomic profile of blood collected from 223 participants and 40 placebo recipients. Pathway-level analysis of HIV-1 negative vaccinees reveals that type I interferons that activate the IRF7 antiviral program and type II interferon-stimulated genes implicated in antigen-presentation are both associated with a reduced risk of HIV-1 acquisition. In contrast, genes upstream and downstream of NF-κB, mTORC1 and host genes required for viral infection are associated with an increased risk of HIV-1 acquisition among vaccinees and placebo recipients, defining a vaccine independent association with HIV-1 acquisition. Our transcriptomic analysis of RV144 trial samples identifies IRF7 as a mediator of protection and the activation of mTORC1 as a correlate of the risk of HIV-1 acquisition.

Efficacy, Immunogenicity, and Safety of a 9-Valent Human Papillomavirus Vaccine: Subgroup Analysis of Participants From Asian Countries.

Background: A 9-valent human papillomavirus-6/11/16/18/31/33/45/52/58 (9vHPV) vaccine extends coverage to 5 next most common oncogenic types (31/33/45/52/58) in cervical cancer versus quadrivalent HPV (qHPV) vaccine. We describe efficacy, immunogenicity, and safety in Asian participants (India, Hong Kong, South Korea, Japan, Taiwan, and Thailand) from 2 international studies: a randomized, double-blinded, qHPV vaccine-controlled efficacy study (young women aged 16-26 years; NCT00543543; Study 001); and an immunogenicity study (girls and boys aged 9-15 years; NCT00943722; Study 002). Methods: Participants (N = 2519) were vaccinated at day 1 and months 2 and 6. Gynecological samples (Study 001 only) and serum were collected for HPV DNA and antibody assessments, respectively. Injection-site and systemic adverse events (AEs) were monitored. Data were analyzed by country and vaccination group. Results: 9vHPV vaccine prevented HPV-31/33/45/52/58-related persistent infection with 90.4%-100% efficacy across included countries. At month 7, ≥97.9% of participants seroconverted for each HPV type. Injection-site AEs occurred in 77.7%-83.1% and 81.9%-87.5% of qHPV and 9vHPV vaccine recipients in Study 001, respectively, and 62.4%-85.7% of girls/boys in Study 002; most were mild to moderate. Conclusions: The 9vHPV vaccine is efficacious, immunogenic, and well tolerated in Asian participants. Data support 9vHPV vaccination programs in Asia. Clinical Trials Registration: NCT00543543; NCT00943722.

HLA class II diversity in HIV-1 uninfected individuals from the placebo arm of the RV144 Thai vaccine efficacy trial.

The RV144 HIV vaccine trial in Thailand elicited antibody responses to the envelope of HIV-1, which correlated significantly with the risk of HIV-1 acquisition. Human leukocyte antigen (HLA) class II molecules are essential in antigen presentation to CD4 T cells for activation of B cells to produce antibodies. We genotyped the classical HLA-DRB1, DQB1, and DPB1 genes in 450 individuals from the placebo arm of the RV144 study to determine the background allele and haplotype frequencies of these genes in this cohort. High-resolution 4 and 6-digit class II HLA typing data was generated using sequencing-based methods. The observed diversity for the HLA loci was 33 HLA-DRB1, 15 HLA-DQB1, and 26 HLA-DPB1 alleles. Common alleles with frequencies greater than 10% were DRB1*07:01, DRB1*09:01, DRB1*12:02, DRB1*15:02, DQB1*02:01/02, DQB1*03:01, DQB1*03:03, DQB1*05:01, DQB1*05:02, DPB1*04:01:01, DPB1*05:01:01, and DPB1*13:01:01. We identified 28 rare alleles with frequencies of less than 1% in the Thai individuals. Ambiguity for HLA-DPB1*28:01 in exon 2 was resolved to DPB1*296:01 by next-generation sequencing of all exons. Multi-locus haplotypes including HLA class I and II loci were reported in this study. This is the first comprehensive report of allele and haplotype frequencies of all three HLA class II genes from a Thai population. A high-resolution genotyping method such as next-generation sequencing avoids missing rare alleles and resolves ambiguous calls. The HLA class II genotyping data generated in this study will be beneficial not only for future disease association/vaccine efficacy studies related to the RV144 study, but also for similar studies in other diseases in the Thai population, as well as population genetics and transplantation studies.

Impact of diabetes mellitus on clinical parameters and treatment outcomes of newly diagnosed pulmonary tuberculosis patients in Thailand.

BACKGROUND: To assess the clinical and laboratory parameters, response to therapy and development of antituberculosis (TB) drug resistance in pulmonary TB (PTB) patients with diabetes mellitus (DM) and without DM. METHODS: Using a prospective design, 227 of 310 new cases of culture-positive PTB diagnosed at the Queen Savang Vadhana Memorial Hospital and the Chonburi Hospital between April 2010 and July 2012 that met the study criteria were selected. Data regarding clinical and laboratory parameters, drug susceptibility and treatment outcomes were compared between PTB patients with DM and those without DM. To control for age, the patients were stratified into two age groups (< 50 and ≥ 50 years) and their data were analysed. RESULTS: Of the 227 patients, 37 (16.3%) had DM, of which 26 (70.3%) had been diagnosed with DM prior to PTB diagnosis and 11 (29.7%) had developed DM at PTB diagnosis. After controlling for age, no significant differences were found between the two groups regarding mycobacterium burden, sputum-culture conversion rate, evidence of multidrug-resistant tuberculosis, frequency of adverse drug events from anti-TB medications, treatment outcomes and relapse rate. The presenting symptoms of anorexia (p = 0.050) and haemoptysis (p = 0.036) were observed significantly more frequently in PTB patients with DM, while the presenting symptom of cough was observed significantly more frequently in PTB patients without DM (p = 0.047). CONCLUSIONS: Plasma glucose levels should be monitored in all newly diagnosed PTB patients and a similar treatment regimen should be prescribed to PTB patients with DM and those without DM in high TB-burden countries.

Correlation of susceptibility of Cryptococcus neoformans to amphotericin B with clinical outcome.

Testing of Cryptococcus neoformans for susceptibility to antifungal drugs by standard microtiter methods has not been shown to correlate with clinical outcomes. This report describes a modified quantitative broth macrodilution susceptibility method showing a correlation with both the patient's quantitative biological response in the cerebrospinal fluid (CSF) and the survival of 85 patients treated with amphotericin B (AMB). The Spearman rank correlation between the quantitative in vitro measure of susceptibility and the quantitative measure of the number of organisms in the patient's CSF was 0.37 (P < 0.01; 95% confidence interval [95% CI], 0.20, 0.60) for the first susceptibility test replicate and 0.46 (P < 0.001; 95% CI, 0.21, 0.62) for the second susceptibility test replicate. The median in vitro estimated response (defined as the fungal burden after AMB treatment) at 1.5 mg/liter AMB for patients alive at day 14 was 5 CFU (95% CI, 3, 8), compared to 57 CFU (95% CI, 4, 832) for those who died before day 14. These exploratory results suggest that patients whose isolates show a quantitative in vitro susceptibility response below 10 CFU/ml were more likely to survive beyond day 14.

End-of-study safety, immunogenicity, and efficacy of quadrivalent HPV (types 6, 11, 16, 18) recombinant vaccine in adult women 24-45 years of age.

BACKGROUND: Previous analyses from a randomised trial in women aged 24-45 years have shown the quadrivalent human papillomavirus (qHPV) vaccine to be efficacious in the prevention of infection, cervical intraepithelial neoplasia (CIN), and external genital lesions (EGLs) related to HPV 6/11/16/18. In this report, we present end-of-study efficacy, safety, and immunogenicity data with a median follow-up time of 4.0 years. METHODS: We enrolled 3819 24-45-year-old women with no history of cervical disease or genital warts in the past 5 years. Women received quadrivalent vaccine or placebo at day 1, and at months 2 and 6. Ascertainment of CIN/EGL was accomplished through Pap testing, genital inspection, and cervicovaginal sampling (every 6 months). The main analysis was conducted in a per-protocol efficacy population (that received three doses, was naive to the relevant HPV types at day 1, and remained free of infection through month 7). Efficacy was also estimated in other naive and non-naive populations. RESULTS: Vaccine efficacy against the combined incidence of persistent infection, CIN/EGL related to HPV6/11/16/18 in the per-protocol population was 88.7% (95% CI: 78.1, 94.8). Efficacy for women who were seropositive and DNA negative for the relevant vaccine HPV type at the time of enrolment who received at least 1 dose was 66.9% (95% CI: 4.3, 90.6). At month 48, 91.5, 92.0, 97.4, and 47.9% of vaccinated women were seropositive to HPV 6/11/16/18, respectively. No serious vaccine-related adverse experiences were reported. CONCLUSIONS: The qHPV vaccine demonstrated high efficacy, immunogenicity, and acceptable safety in women aged 24-45 years, regardless of previous exposure to HPV vaccine type.

HLA class I serotypes and cytotoxic T-lymphocyte responses among human immunodeficiency virus-1-uninfected Thai volunteers immunized with ALVAC-HIV in combination with monomeric gp120 or oligomeric gp160 protein boosting.

Antigen-induced cellular immunogenicity may vary between populations due to differences in human leukocyte antigen (HLA) diversity and, hence, may play a critical role in the protection afforded by vaccines. In the setting of two, phase I/II human immunodeficiency virus-1 vaccine trials of a recombinant canarypox prime, and boosting with either recombinant monomeric gp120 or oligomeric gp160, we assessed the association between specific human leukocyte antigen (HLA) class I serotypes and the presence of cytotoxic T-lymphocyte response measured by 51Cr-release assay. HLA class I serotypes A11, A24, A33, B46, and B75 were the most common, present in 10% or more of 245 individuals studied. Forty of 187 (21.4%) Thai adults who received either ALVAC-HIV with gp120 or oligomeric gp160 or ALVAC alone had a precursor cytolytic CD8 T-cell response (pCTL). HLA-B44 was positively and significantly associated with a pCTL response (odds ratio 7.6, 95% CI: 2.7-21.2), whereas B46 was negatively associated but not robust when adjusted for multiple comparisons. Responses to Env proteins accounted for the majority (nine of 11) of pCTL activity among those persons with B44. This HLA class I serotype occurred in 9.4% of participants overall (including the placebo group), less commonly than what is reported from populations of European ancestry. These results strengthen the importance of assessing HLA class I distributions in conjunction with studies of vaccines designed to elicit cellular immunity in different populations.

Effects of cigarette smoking on quinine pharmacokinetics in malaria.

OBJECTIVE: Quinine is an important antimalarial drug that is metabolised mainly by the hepatic mixed-function microsomal enzyme cytochrome P(450). Cigarette smoking in healthy volunteers has been reported to enhance quinine clearance. The present study evaluated the effects of smoking on quinine pharmacokinetics in patients with uncomplicated falciparum malaria treated with a 7-day course of oral quinine. Of 22 studied male patients, 10 were regular smokers and 12 were non-smokers. METHODS: All patients were treated with a 7-day oral regimen of quinine sulfate (10 mg salt/kg three times a day). Serial venous blood samples were taken for quinine levels before and during treatment at 12 h and 24 h and then daily until day 7. Plasma quinine and 3-hydroxyquinine concentrations were assayed using high-performance liquid chromatography. Quinine pharmacokinetics were evaluated using non-compartmental modelling. RESULTS: All patients recovered, and there were no significant differences in clinical responses or cure rates between the two studied groups ( P> or =0.32). The median (range) fever clearance time was 51 h (4-152 h) and mean (SD) parasite clearance time was 74+/-28 h. The overall median times to maximum concentrations of quinine and its main metabolite 3-hydroxyquinine were 1.5 days and 4.0 days, respectively. The maximum concentrations of quinine were approximately tenfold higher than 3-hydroxyquinine. There were no significant differences in any pharmacokinetic variables for the parent compound or metabolite between the two groups. The median area under the plasma drug concentration-time curve to day 7 (AUC(0-7)) of quinine in non-smokers was 67.0 micro g/ml/day and in smokers was 51.3 micro g/ml/day, and AUC(0-7) values of 3-hydroxyquinine were 6.2 micro g/ml/day and 4.8 micro g/ml/day, respectively. CONCLUSION: These results indicated that cigarette smoking has no significant effects on quinine pharmacokinetics or the therapeutic response in patients with falciparum malaria.

A human volunteer challenge model using frozen bacteria of the new epidemic serotype, V. cholerae O139 in Thai volunteers.

A total of 35 volunteers were recruited for an IRB-approved inpatient dose-escalation challenge. The goal was to identify a dose that produced an observed cholera attack rate > or =80% and an illness of sufficient severity during the defined study period such that the model would be useful for determining vaccine protection. Volunteers were challenged in groups of 5 with V. cholerae O139 that had been reconstituted immediately before use. Only 2 out of 5 volunteers who received the lowest dose (4.3 x 10(4) cfu) had diarrhea. As the inoculum size increased, the attack rate of diarrhea increased to 3-4 of 5 volunteers. At the highest dose tested, approximately 5 x 10(7) cfu, the attack rate was 73%. We recommend the use of frozen V. Cholera O139 in a human experimental challenge model to assess cholera vaccine efficacy (VE) in a cholera endemic area but with 4 days observation period before initiation of tetracycline to allow assessment of severity.

A prospective study of AIDS-associated cryptococcal meningitis in Thailand treated with high-dose amphotericin B.

OBJECTIVE: To assess kinetic of cryptococci in the cerebrospinal fluid (CSF) and outcome of AIDS-associated cyptococcal meningitis after high-dose amphotericin B. PATIENTS AND METHODS: A prospective study involving Thai adults (n=106) with cryptococcal meningitis associated with AIDS was conducted to determine the kinetic of cryptococci in CSF and prognostic factors affecting survival after high-dose amphotericin B (0.7 mg/kg/day) followed by oral azole treatment. Cerebrospinal fluids were collected for cryptococcal count and culture at weekly intervals for at least 2 weeks or until CSF cultures were negative for cryptococci. All patients were followed monthly for 1 year or until death in order to detect relapse or occurrence of any other opportunistic infection. RESULTS: A total of 106 AIDS patients with cryptococcal meningitis were enrolled. The geometric mean (range) total and viable cryptococcal counts in CSF on admission were 430,000 (1000 to 3.4 x 10(7)) and 31,000 (10 to 1.4 x 10(7)) per ml, respectively. Both total and viable cryptococcal counts declined monoexponentially with an elimination half life of 4 days. The cumulative CSF yeast clearance rates were 38% and 56% at 2 and 4 weeks, respectively. Early death was associated significantly with previous history of weight loss [relative risk (RR)=2.2; 95% CI, 1.2-3.9], Glasgow Coma Score <13 (RR=2.33; 95% CI, 1.55-3.50), and hypoalbuminaemia (P<0.001). Later mortality was associated delayed CSF yeast clearance (RR=3.6; 95% CI, 1.9--6.4) and relapse (RR=3.9; 95% CI, 1.4-10.8). CONCLUSION: High-dose amphotericin B was not as effective as previously thought. Cumulative mortality at 2 weeks, 4 weeks and 1 year were 16%, 24% and 76%, respectively.

AIDSVAX (MN) in Bangkok injecting drug users: a report on safety and immunogenicity, including macrophage-tropic virus neutralization.

A randomized, double-blind, placebo-controlled phase I/II study of AIDSVAX (MN) was conducted among injecting drug users in Bangkok, Thailand. Four doses of vaccine (300 microg of MN-rgp120 in alum) or placebo (alum) were given at study entry and at 1, 6, and 12 months. The objectives of the study were to evaluate (1) the feasibility of conducting vaccine trials in this population; (2) the safety of this candidate AIDS vaccine; and (3) the immunogenicity of this vaccine. Thirty-three volunteers (22 vaccine and 11 placebo recipients) were recruited. None were lost to follow-up during the 18-month study. Mild reactogenicity was noted, which was similar in both vaccine and placebo recipients. The vaccine induced anti-HIV-1 antibody in all vaccine recipients. Maximal titers of binding antibodies of MN-rgp120 and the V3 domain of MN-rgp120 were induced after the third (6 month) dose while maximal neutralizing antibodies followed the fourth (12 month) dose. The vaccine-induced antibodies from several volunteers were capable of neutralizing macrophage-tropic, subtype B viruses (301660 and JRCSF) detected in a PBMC-based assay. Binding and neutralizing antibodies declined about 10-fold in the 6 months after the last boost. Two vaccinees became infected during the trial, both with subtype E viruses. A phase III efficacy trial, using a bivalent gp120 vaccine containing antigens from a subtype B virus (MN) and a subtype E virus (A244), was initiated in March 1999 in injecting drug users in Bangkok.

Nonadherence in tuberculosis treatment among HIV patients attending Bamrasnaradura Hospital, Nonthaburi.

OBJECTIVE: To determine the clinical manifestations, outcome and nonadherence, in tuberculosis (TB) among HIV patients in Bamrasnaradura Hospital, Nonthaburi. DESIGN: A retrospective cohort study; hospital record files were reviewed over 11 months. A total of 200 consecutive HIV patients were entered and followed for a 6 months period of their TB treatment. Sociodemographic data, symptoms and signs and results of investigation tests were recorded at the time of presentation, while diagnosis, and clinical outcome were done at the end of the follow-up time. RESULTS: Extrapulmonary tuberculosis (58%) was more common than pure pulmonary involvement (42%). Lymphadenopathy (52%) was the commonest sign on physical examination. Chest X-rays were positive in 55 per cent cases, while AFB examination was positive in 48.5 per cent from the sputum and 46 per cent from lymph node aspirate specimens. After 6 months of treatment, 30 per cent patients were still alive, 12 per cent had died, and 50 per cent were lost to follow-up. Factors such as low socioeconomic status (p < 0.001), being newly diagnosed with TB (p < 0.001), past history of TB (p < 0.003), etc., were statistically significant in predicting the likely nonadherence in TB treatment among HIV patients. CONCLUSION: In HIV-infected individual, tuberculosis presents more often with extrapulmonary involvement, and the diagnosis is not difficult. While treatment of tuberculosis is successful, patients' compliance is the biggest problem in managing them.

Monotherapy with sodium artesunate for uncomplicated falciparum malaria in Thailand: a comparison of 5- and 7-day regimens.

We compared the safety and efficacy of two treatment regimens using sodium artesunate in 91 randomized patients with uncomplicated falciparum malaria acquired in Thailand. One group of 45 patients received 400 mg of artesunate on the first day of treatment and then 200 mg daily for 4 days for a total of 1200 mg (group I: 5-day treatment). A second group of 46 patients received 400 mg of artesunate on the first day of treatment and then 200 mg daily for 6 days for a total of 1600 mg (group II: 7-day treatment). Both regimens were well tolerated. All patients were followed for a total of 28 days. By the third day of treatment, most patients were blood smear negative for parasites. Eighty-two patients completed the 28-day follow-up period and were used for describing the cure rate. All patients treated with the 5-day regimen were cured. In the 7-day treatment group, 98% (39 of 40) of the patients were cured; one patient developed late recrudescence (RI). There were no significant differences in fever clearance or parasite clearance between the two groups. However, 13 patients (five in group I and eight in group II) developed Plasmodium vivax infection during the follow-up period. We conclude that 5- or 7-day regimens of sodium artesunate with a total dose of 1200-1600 mg are effective and safe in treating falciparum malaria acquired in Thailand.

Open randomized trial of oral artemether alone and a sequential combination with mefloquine for acute uncomplicated falciparum malaria.

One hundred fifty-one patients with acute uncomplicated falciparum malaria were enrolled in a randomized, open-label study of oral artemether given alone for five or seven days or a sequential treatment of oral artemether followed by mefloquine. Forty patients received oral artemether, 100 mg initially, then 50 mg every 12 hr for a total dose of 500 mg over a five-day period: Group I. Fifty-eight patients received oral artemether, 100 mg initially, then 50 mg every 12 hr for a total dose of 750 mg over a seven-day period: Group II. Fifty-three patients received oral artemether, 200 mg every 8 hr for a total dose of 600 mg, followed 8 hr later with mefloquine (1,250 mg divided into two doses given 6 hr apart: Group III. All patients were admitted to the hospital for 28 days to exclude reinfection and 131 patients remained through the 28-day follow-up. Only two, nine, and nine patients in Groups I, II, and III, respectively, left the hospital prior to study completion for reasons unrelated to their treatment. Cure rates for the three groups were 74% (28 of 38) for Group I, 98% (48 of 49) for Group II, and 98% (43 of 44) for Group III. Mean fever and parasite clearance times were not significantly different (32.8, 27.5, and 31.4 hr for fever clearance times and 40.2, 40.6, and 36.7 hr for parasite clearance times of Groups I, II, and III, respectively) nor were any adverse effects seen. In vitro drug susceptibility testing of admission and recrudescent parasite isolates was conducted for 10 patients. These data showed no decreased response to artemether or dihydroartemisinin in recrudescent isolates when compared with admission isolates. The results of this study suggest that sequential treatment for two days with oral artemether (600 mg) followed by mefloquine (1,250 mg) is effective and well-tolerated in patients with acute uncomplicated falciparum malaria and may be an alternative treatment for multidrug-resistant falciparum malaria, particularly useful for treating patients in rural areas where the period of admission to the hospital should be as short as possible. A seven-day regimen of artemether alone (750 mg) is also very effective, yet requires prolonged administration of drug after malaria symptoms disappear.

Risk behaviours and comprehension among intravenous drug users volunteered for HIV vaccine trial.

Out of 91 volunteers enrolled for the HIV vaccine trial, only 33 volunteers were eligible for vaccination. Of 33 volunteers recruited, 59 per cent of them had incomes of more than 5,000 Baht/ month. The median duration of drug addicts was 15 years (range 1-26 years) and 42 per cent never used condoms during sexual intercourse. As far as consent comprehension was concerned, all of them understood.

PIP: With HIV seroprevalence rates of 35-40%, Thai intravenous drug users are an obvious target group for anti-HIV vaccine trials. The Ministry of Public Health of Thailand recently approved clinical trials of the Genentech MN rgp 120/HIV-1 candidate vaccine among recovering intravenous drug users enrolled in a methadone treatment center in Bangkok. To evaluate safety and immunogenicity factors and assemble a relatively low-risk group, 91 potential volunteers from this center were screened (history, physical examination, and blood and urine analysis). Only 33 passed all of the screening procedures; the major causes of ineligibility were HIV seropositivity (14 cases) and impaired liver function test (10 cases). The 33 eligibles had a median duration of drug addiction of 15 years. The majority had a secondary education or above and a monthly income exceeding 5000 Baht (US$200). Never-use of condoms was acknowledged by 14 of the eligible volunteers, but all 33 denied relationships with commercial sex workers. Among those selected for the trial, 23 believed a successful vaccine against AIDS is likely and 30 thought the vaccine they received was effective; however, 12 were concerned the vaccine would enhance disease progression. After 12 months of counseling and participation in the vaccine trial, nine volunteers were drug and methadone-free. Overall, these findings indicate that intravenous drug users can successfully participate in vaccine trials if there is adequate pre-screening.

Comparative clinical trial of artesunate followed by mefloquine in the treatment of acute uncomplicated falciparum malaria: two- and three-day regimens.

The difficulties in treating drug-resistant falciparum malaria in Thailand are compounded by the necessity of giving antimalarials over long periods of time. The resultant decrease in patient compliance not only lowers cure rates but also predisposes to the further spread of drug resistance. We compared the efficacy of two sequential treatment regimens given over two and three days in 111 patients with acute uncomplicated falciparum malaria. Sixty-seven patients received two 400-mg doses of artesunate (total dose = 800 mg) followed by two doses of mefloquine (750 mg given immediately and 500 mg 12 hr later; total dose = 1,250 mg) in Group 1. Forty-four patients (Group II) received four 200-mg doses of artesunate (total dose = 800 mg) given 12 hr apart followed by a mefloquine regimen similar to that for Group I. All patients were admitted to hospital in Bangkok for 28 days to preclude reinfection. Ninety-six patients completed the study. Cure rates for the two groups were 84% (49 of 58) for Group I and 100% (38 of 38) for Group II. The mean parasite clearance time and fever clearance time were significantly shorter in Group II (P < 0.02). There were no serious adverse reactions. All nine of the treatment failures in Group I were of the RI types. The results indicate that the sequential treatment with artesunate followed by mefloquine given over three days is effective and well-tolerated in patients with acute, uncomplicated falciparum malaria and suitable as an alternative treatment for multidrug-resistant falciparum malaria.

Treatment of acute, uncomplicated, falciparum malaria with oral dihydroartemisinin.

A clinical trial of oral dihydroartemisinin for the treatment of acute, uncomplicated, falciparum malaria involved 53 adult patients in Thailand. Each received a total dose of 480 mg over 7 days (120 mg given immediately, followed by 60 mg/day) after being admitted to the Hospital for Tropical Diseases in Bangkok for 28 days. Most (92%) completed the 28-day follow-up but four patients left the hospital early, for reasons unrelated to their treatment. Most patients showed clinical improvement 1-3 days after starting treatment and none suffered from serious adverse reactions. The cure rate was 90% (44/49). The mean (S.D.) parasite-clearance time was 40.4 (14.1) h and the mean fever-clearance time was 37.0 (30.2) h. Seven patients had a brief increase in parasitaemia after initiation of treatment but subsequent counts declined dramatically. Five patients who failed treatment (RI response) were successfully treated with quinine plus tetracycline for 7 days. No RII or RIII responses were observed. These findings indicate that treatment with oral dihydroartemisinin is effective and well tolerated, and that dihydroartemisinin may be suitable as an alternative treatment for acute, uncomplicated, falciparum malaria. Comparisons with other conventional antimalarial drugs in a large, double-blind, randomized trial and studies of dihydroartemisinin in combination with other, long-acting antimalarials are needed.

A randomized comparative study of albendazole and thiabendazole in chronic strongyloidiasis.

An open randomized study for comparing the efficacy of albendazole and thiabendazole in chronic strongyloidiasis was done in 1990-1992. All 35 patients with positive stool examinations for Strongyloides stercoralis were divided randomly into two groups. 23 patients (group A) received albendazole (400 mg twice daily for 5 days) and 12 patients (group B) received thiabendazole (1 g twice daily for 5 days). All patients except four patients in group A were admitted in the Hospital for Tropical Diseases for 21 days for monitoring side effects (D0-7) and stool examination (D0, D7, 8, 9, D21, 22, 23). Methods of stool examination included: direct microscopy of saline smear, formalin ether concentration, culture (Harada and Mori method) and larva count (Stool and Sasa method). Cure was defined as negative stool examination done at 21 days after medication by all above methods. The cure rate for group A was 95% (only one failed to clear the parasite at D21) and the cure rate for group B was 100%. But there was no statistical difference between the two. Mild changes of transminases observed in 5/23 patients who received albendazole, but none developed clinical hepatitis.