A phase II clinical trial of a Vi-DT typhoid conjugate vaccine in healthy Indonesian adolescents and adults: one-month evaluation of safety and immunogenicity.

BACKGROUND: Typhoid fever is commonly found until today, especially in developing countries. It has fatal complications and measures must be taken to reduce the incidence of typhoid. Vaccinations are a key factor in prevention. This is a phase II randomized observer-blind clinical trial on a novel Vi-DT conjugate vaccine on 200 subjects 12 to 40 years of age. METHODS: Subjects were screened for eligibility after which a blood sample was taken and one dose of vaccine was administered. Investigational vaccine used was Vi-DT and control was Vi-PS. Twenty-eight days after vaccination, subjects visited for providing blood sample to assess immunogenicity and were asked about local and systemic adverse reactions that occurred in the first 28 days. RESULTS: Subjects had minor adverse reactions. Pain was the most common local reaction. Muscle pain was the most common systemic reaction. There were no serious adverse events up to 28 days post vaccination. Seroconversion rates were 100% in the Vi-DT group and 95.96% in the Vi-PS group. Post vaccination GMTs were increased in both groups but it was significantly higher in the Vi-DT group (p < 0.001). CONCLUSIONS: Vi-DT typhoid conjugate vaccine is safe and immunogenic in healthy Indonesian subjects 12 to 40 years. TRIAL REGISTRATION: Approved by ClinicalTrials.gov. CLINICAL TRIAL REGISTRATION NUMBER: NCT03460405. Registered on 09/03/2018. URL: https://clinicaltrials.gov/ct2/show/NCT03460405 .

Protectivity and safety following recombinant hepatitis B vaccine with different source of bulk compared to hepatitis B (Bio Farma) vaccine in Indonesia.

PURPOSE: Indonesia, a high populous and the second-highest country in epidemicity of hepatitis B in South-East Asia require maintaining its capacity of monovalent hepatitis B production to keep up with both the national immunization program and global needs. To keep the sustainability of the vaccine, a new bulk is needed to be made available. This study aims to evaluate the immunogenicity and safety of Bio Farma newly formulated recombinant hepatitis B vaccines, which came from different sources of bulk, compared to the already registered hepatitis B vaccine. MATERIALS AND METHODS: An experimental, randomized, double-blind, cohort intervention phase II clinical trial was conducted on three recombinant hepatitis B vaccines from different bulk sources, with Bio Farma registered hepatitis B vaccine as the control group. A total of 536 participants around age 10 to 40 years old were thricely vaccinated with twice serological assessments. The subject's safety was monitored for 28 days after each vaccination. RESULTS: Of 536 enrolled participants, 521 finished the vaccination and serology assessments. The investigational products were proven not to be inferior to the control. All vaccines were well tolerated. No differences in rates of local and systemic reactions were seen between the investigational products and control. No serious adverse event was found to be related to the investigational vaccines. CONCLUSION: Investigational vaccines are shown to be equally immunogenic and safe as the control vaccine.

A novel Vi-diphtheria toxoid typhoid conjugate vaccine is safe and can induce immunogenicity in healthy Indonesian children 2-11 years: a phase II preliminary report.

BACKGROUND: Typhoid fever caused by Salmonella enteric serovar Typhi (S. Typhi) is a common cause of morbidity in the world. In 2017, 14.3 million cases of Typhoid and paratyphoid fever occurred globally. School age children between 3 to 19 years old are the most affected. Poor sanitation and multi drug resistance have increased the need for vaccines to reduce the global burden of disease. Based on previous trials, typhoid conjugate vaccines have longer- lasting protection, higher efficacy, require fewer doses and are suitable from infancy that allows them to be incorporated into the routine immunization program. Our previous phase I trial proved that a novel Vi-DT typhoid conjugate vaccine is safe and immunogenic in subjects 2-5 and 18-40 years. Our phase II trial consisted of subjects 6 months to 40 years. Our previously published paper on subjects 6 to < 24 months proved that this vaccine is safe and immunogenic for this age group. Therefore, with this paper we aimed to evaluate the safety and immunogenicity in children 2-11 years. METHODS: A randomized, observer-blind, superiority design of Vi-DT Typhoid conjugate vaccine compared to Vi-polysaccharide vaccine (Vi-PS) phase II study was conducted from October 2018 to December 2018 where 200 subjects aged 2-11 years were recruited. A blood sample prior to vaccination was taken, followed by administration of a single dose of either test vaccine (Vi-DT) or control vaccine (Vi-PS) and then a second blood sample was collected 28 days post vaccination. Adverse reactions were assessed and antibody increment was evaluated at 28 days post vaccination through collected serum sample. RESULTS: Pain was the most common local reaction. Fever and muscle pain were the most common systemic reactions. Both Vi-DT and Vi-PS groups had roughly the same number of adverse reactions. At 28 days post vaccination, 100% of subjects in the Vi-DT group and 93% of subjects in the Vi-PS group produced antibody increment ≥4 times. The Vi-DT group produced a higher GMT as compared to Vi-PS. CONCLUSION: Vi-DT vaccine is safe and immunogenic in children 2-11 years old. TRIAL REGISTRATION: Trial registration number: NCT03460405 .

One-month follow up of a randomized clinical trial-phase II study in 6 to <24 months old Indonesian subjects: Safety and immunogenicity of Vi-DT Typhoid Conjugate Vaccine.

INTRODUCTION: World Health Organization estimates the annual global incidence of typhoid fever at 11-21 million cases and approximately 128 000 to 161 000 deaths. The currently used Vi-polysaccharides (Vi-PS) vaccines have been proven to be safe and efficacious in children 2 years and above. However, poor immunogenicity of Vi-PS was observed in children below 2 years of age. This Phase II study is the continuation of the previously published Phase I study that aims to evaluate the safety and immunogenicity of a novel Vi-DT Typhoid Conjugate Vaccine (Bio Farma) in subjects 6 to <24 months. METHODS: An interventional, blinded, comparative, randomized phase II study was conducted from July 2018 until January 2019. There were 200 healthy subjects divided into two groups: trial and control groups. Inactivated poliovirus vaccine was given to control group. Immediate and delayed local and systemic reactions up to 28 days post vaccination were recorded. Antibody titers were measured prior to vaccination (V1) and 28 days post vaccination (V2). RESULT: The study showed that the seroconversion of Vi-DT vaccine 98.99%. One dose of Vi-DT vaccine induced higher geometric mean titers (GMT) in all subjects compared to that of baseline. Pain was the most common immediate and delayed local reaction. Immediate and delayed systemic reactions that mostly occurred was fever. There were no serious adverse events reported within 28 days post vaccination. CONCLUSION: The novel typhoid Vi-DT conjugate vaccine is safe and immunogenic in children 6 to <24 months. TRIAL REGISTRATION NUMBER: NCT03460405.

Six-month follow up of a randomized clinical trial-phase I study in Indonesian adults and children: Safety and immunogenicity of Salmonella typhi polysaccharide-diphtheria toxoid (Vi-DT) conjugate vaccine.

INTRODUCTION: There is a high global incidence of typhoid fever, with an annual mortality rate of 200,000 deaths. Typhoid fever also affects younger children, particularly in resource-limited settings in endemic countries. Typhoid vaccination is an important prevention tool against typhoid fever. However, the available polysaccharide typhoid vaccines are not recommended for children under 2 years of age. A new typhoid conjugate Vi-diphtheria toxoid (Vi-DT) vaccine has been developed for infant immunization. We aimed to define the safety and immunogenicity of the Vi-DT vaccine among adults and children in Indonesia. METHODS: An observational, blinded, comparative, randomized, phase I safety study in two age de-escalating cohorts was conducted in East Jakarta, Indonesia, from April 2017 to February 2018. We enrolled 100 healthy subjects in 2 age groups: adults and children (18-40 and 2-5 years old). These groups were randomized into study groups (Vi-DT vaccine), and comparator groups (Vi-polysaccharide (Vi-PS) vaccine and another additional vaccine) which was administered in 4 weeks apart. Subjects were followed up to six months. RESULT: One hundred healthy adults and children subjects completed the study. The Vi-DT and Vi-PS vaccines showed no difference in terms of intensity of any immediate local and systemic events within 30 minutes post-vaccination. Overall, pain was the most common local reaction, and muscle pain was the most common systemic reaction in the first 72 hours. No serious adverse events were deemed related to vaccine administration. The first and second doses of the Vi-DT vaccine induced seroconversion and higher geometric mean titers (GMT) in all subjects compared to that of baseline. However, in terms of GMT, the second dose of Vi-DT did not induce a booster response. CONCLUSION: The Vi-DT vaccine is safe and immunogenic in adults and children older than two years. A single dose of the vaccine is able to produce seroconversion and high GMT in all individuals.

Decreased plasma levels of the endothelial protective sphingosine-1-phosphate are associated with dengue-induced plasma leakage.

BACKGROUND: A transient endothelial hyperpermeability is a hallmark of severe dengue infections. Sphingosine-1-phosphate (S1P) maintains vascular integrity and protects against plasma leakage. We related plasma S1P levels to dengue-induced plasma leakage and studied mechanisms that may underlie the decrease in S1P levels in dengue. METHODS: We determined circulating levels of S1P in 44 Indonesian adults with acute dengue and related levels to plasma leakage, as determined by daily ultrasonography, and to levels of its chaperone apolipoprotein M, other lipoproteins and platelets. RESULTS: Plasma S1P levels were decreased during dengue and patients with plasma leakage had lower median levels compared to those without (638 vs. 745 nM; p < 0.01). ApoM and other lipoprotein levels were also decreased during dengue, but did not correlate to S1P levels. Platelet counts correlated positively with S1P levels, but S1P levels were not higher in frozen-thawed platelet rich plasma, arguing against platelets as an important cellular source of S1P in dengue. CONCLUSIONS: Decreased plasma S1P levels during dengue are associated with plasma leakage. We speculate that decreased levels of ApoM underlies the lower S1P levels. Modulation of S1P levels and its receptors may be a novel therapeutic intervention to prevent plasma leakage in dengue.

West Nile virus documented in Indonesia from acute febrile illness specimens.

We report the presence of West Nile virus in a cryopreserved, dengue-negative serum specimen collected from an acute fever case on Java in 2004-2005. The strain belongs to genotype lineage 2, which has recently been implicated in human outbreaks in Europe.

The predictive diagnostic value of serial daily bedside ultrasonography for severe dengue in Indonesian adults.

BACKGROUND: Identification of dengue patients at risk for progressing to severe disease is difficult. Significant plasma leakage is a hallmark of severe dengue infection which can suddenly lead to hypovolemic shock around the time of defervescence. We hypothesized that the detection of subclinical plasma leakage may identify those at risk for severe dengue. The aim of the study was to determine the predictive diagnostic value of serial ultrasonography for severe dengue. METHODOLOGY/PRINCIPAL FINDINGS: Daily bedside ultrasounds were performed with a handheld ultrasound device in a prospective cohort of adult Indonesians with dengue. Timing, localization and relation to dengue severity of the ultrasonography findings were determined, as well as the relation with serial hematocrit and albumin values. The severity of dengue was retrospectively determined by WHO 2009 criteria. A total of 66 patients with proven dengue infection were included in the study of whom 11 developed severe dengue. Presence of subclinical plasma leakage at enrollment had a positive predictive value of 35% and a negative predictive value of 90% for severe dengue. At enrollment, 55% of severe dengue cases already had subclinical plasma leakage, which increased to 91% during the subsequent days. Gallbladder wall edema was more pronounced in severe than in non-severe dengue patients and often preceded ascites/pleural effusion. Serial hematocrit and albumin measurements failed to identify plasma leakage and patients at risk for severe dengue. CONCLUSIONS/SIGNIFICANCE: Serial ultrasonography, in contrast to existing markers such as hematocrit, may better identify patients at risk for development of severe dengue. Patients with evidence of subclinical plasma leakage and/or an edematous gallbladder wall by ultrasonography merit intensive monitoring for development of complications.