A Randomized Dose-Escalating Phase I Trial of a Replication-Deficient Lymphocytic Choriomeningitis Virus Vector-Based Vaccine Against Human Cytomegalovirus.

BACKGROUND: A vaccine (HB-101) consisting of 2 nonreplicating lymphocytic choriomeningitis virus (LCMV) vectors expressing the human cytomegalovirus antigens glycoprotein B (gB) and the 65-kD phosphoprotein (pp65), respectively, is in development to prevent cytomegalovirus infection. METHODS: HB-101 was tested in cytomegalovirus-naive, healthy adults in a randomized, double-blind, placebo-controlled, dose-escalation Phase I trial. Fifty-four subjects received low, medium, or high dose of HB-101 or placebo by intramuscular administration at Month 0, 1, and 3. Safety and immunogenicity were the respective primary and secondary endpoints. Subjects were followed for 12 months after the initial immunization. RESULTS: Vaccination was associated with transient mild to moderate adverse events. HB-101 administration induced dose-dependent gB- and pp65-specific cellular responses, dominated by pp65-specific CD8 T cells, a high fraction of which were polyfunctional. Two administrations were sufficient to elicit dose-dependent gB-binding and cytomegalovirus-neutralizing antibodies (Abs). Cytomegalovirus-specific immune responses were boosted after each administration. Only 1 of 42 vaccine recipients mounted a transient LCMV vector-neutralizing Ab response. CONCLUSIONS: HB-101 was well tolerated and induced cytomegalovirus-specific polyfunctional CD8 T-cell and neutralizing Ab responses in the majority of subjects. Lack of vector-neutralizing Ab responses should facilitate booster vaccinations. These results justify further clinical evaluation of this vaccine candidate.

Extracellular Vesicles: A New Promise for the Prevention of Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD) despite numerous efforts of neonatologists remains one of the most frequent and long-lasting chronic respiratory diseases consequent to extreme preterm birth. New clinical trials are exploring the possible use of mesenchymal stem cells (MSCs) and especially their products, extracellular vesicles (EVs), that overcome some of the possible issues related to the use of live cells. MSCs already reached clinical implementation; MSC-EVs, on the contrary, showed extremely promising results in the preclinical setting but are still waiting their first in human results that are likely to happen soon. KEY POINTS: · BPD is one of the most frequent complications of preterm birth, and its prevention lacks an effective tool.. · EVs have shown encouraging results in preclinical animal models.. · Technical and biological advancements are needed before routine clinical use..

Extracellular Vesicles From Mesenchymal Umbilical Cord Cells Exert Protection Against Oxidative Stress and Fibrosis in a Rat Model of Bronchopulmonary Dysplasia.

Oxidative stress and fibrosis are important stress responses that characterize bronchopulmonary dysplasia (BPD), a disease for which only a therapy but not a cure has been developed. In this work, we investigated the effects of mesenchymal stromal cells-derived extracellular vesicles (MSC-EVs) on lung and brain compartment in an animal model of hyperoxia-induced BPD. Rat pups were intratracheally injected with MSC-EVs produced by human umbilical cord-derived MSC, following the Good Manufacturing Practice-grade (GMP-grade). After evaluating biodistribution of labelled MSC-EVs in rat pups left in normoxia and hyperoxia, oxidative stress and fibrosis investigation were performed. Oxidative stress protection by MSC-EVs treatment was proved both in lung and in brain. The lung epithelial compartment ameliorated glycosaminoglycan and surfactant protein expression in MSC-EVs-injected rat pups compared to untreated animals. Pups under hyperoxia exhibited a fibrotic phenotype in lungs shown by increased collagen deposition and also expression of profibrotic genes. Both parameters were reduced by treatment with MSC-EVs. We established an in vitro model of fibrosis and another of oxidative stress, and we proved that MSC-EVs suppressed the induction of αSMA, influencing collagen deposition and protecting from the oxidative stress. In conclusion, intratracheal administration of clinical-grade MSC-EVs protect from oxidative stress, improves pulmonary epithelial function, and counteracts the development of fibrosis. In the future, MSC-EVs could represent a new cure to prevent the development of BPD.

Industrial hemp (Cannabis sativa L.) field cultivation in a phytoattenuation strategy and valorization potential of the fibers for textile production.

This paper evaluates the valorization potential of industrial hemp (Cannabis sativa L.) fibers produced on HM-contaminated soil as a safe feedstock for the textile industry. The chosen strategy was phytoattenuation, which combines the progressive soil quality improvement of contaminated land using phytoremediation techniques with the production of safe non-food biomass. A field experiment was set up with two hemp cultivars on a site contaminated with Cd, Pb, and Zn and on a nearby site containing clean soil as a control. Stem height and diameter were analyzed, as well as stem and fiber yield and the HM concentrations in the fibers, which were compared to legal safety standards and toxicity thresholds used in the textile industry. The hemp cultivar Carmagnola Selected (CS) had a significantly higher stem and bigger stem diameter compared to cultivar USO 31 on both sites. Stem yields showed a decrease of 30% and 50%, respectively, for both hemp cultivars grown on the contaminated site. However, the stem yield of CS growing on the contaminated site was similar to the stem yield of USO 31 growing on the control site, indicating that hemp cultivation on contaminated soil can be economically viable. Total and extractable Cd, Pb, and Zn fiber concentrations were far below the toxicity standards for textile production purposes. These results are promising in terms of the potential valorization of contaminated land with hemp cultivation and the development of a non-food value chain within a phytoattenuation strategy.

A review of rotavirus infection in and vaccination of human immunodeficiency virus-infected children.

Diarrhea caused by infection with rotavirus annually results in an estimated 611,000 deaths among infants and young children <5 years of age worldwide, and these deaths primarily occur in developing countries. Infection with human immunodeficiency virus (HIV) is also common among young children in many developing countries, particularly in sub-Saharan Africa and Asia. The need for a vaccine to reduce the number of deaths caused by rotavirus infection among children in developing countries is substantial, but current rotavirus vaccines comprise live attenuated oral viruses, the behaviors of which are unknown in HIV-infected children. Therefore, we reviewed available data on natural rotavirus infection in HIV-infected children and examined unpublished data on a small group of HIV-infected infants in South Africa who were given a live rotavirus vaccine. Together, these data suggest that vaccination programs against rotavirus infection could include HIV-infected populations. However, studies addressing the safety, reactogenicity, and immunogenicity of rotavirus vaccines in an HIV-infected population are urgently needed.

Preferred product characteristics for therapeutic vaccines to improve tuberculosis treatment outcomes: Key considerations from World Health Organization consultations.

Treating tuberculosis (TB) requires a multidrug course of treatment lasting 6 months, or longer for drug-resistant TB, which is difficult to complete and often not well tolerated. Treatment failure and recurrence after end-of-treatment can have devastating consequences, including progressive debilitation, death, the transmission of Mycobacterium tuberculosis - the infectious agent responsible for causing TB - to others, and may be associated with the development of drug-resistant TB. The burden on health systems is important, with severe economic consequences. Vaccines have the potential to serve as immunotherapeutic adjuncts to antibiotic treatment regimens for TB. A therapeutic vaccine for TB patients, administered towards completion of a prescribed course of drug therapy or at certain time(s) during treatment, could improve outcomes through immune-mediated control and even clearance of bacteria, potentially prevent re-infection, and provide an opportunity to shorten and simplify drug treatment regimens. The preferred product characteristics (PPC) for therapeutic TB vaccines described in this document are intended to provide guidance to scientists, funding agencies, public and private sector organizations developing such vaccine candidates. This document presents potential clinical end-points for evidence generation and discusses key considerations about potential clinical development strategies.

Efficacy and safety of an oral live attenuated human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in Latin American infants: a randomised, double-blind, placebo-controlled phase III study.

BACKGROUND: Peak incidence of rotavirus gastroenteritis is seen in infants between 6 and 24 months of age. We therefore aimed to assess the 2-year efficacy and safety of an oral live attenuated human rotavirus vaccine for prevention of severe gastroenteritis in infants. METHODS: 15 183 healthy infants aged 6-13 weeks from ten Latin American countries randomly assigned in a 1 to 1 ratio to receive two oral doses of RIX4414 or placebo at about 2 and 4 months of age in a double-blind, placebo-controlled phase III study were followed up until about 2 years of age. Primary endpoint was vaccine efficacy from 2 weeks after dose two until 1 year of age. Treatment allocation was concealed from investigators and parents of participating infants. Efficacy follow-up for gastroenteritis episodes was undertaken from 2 weeks after dose two until about 2 years of age. Analysis was according to protocol. This study is registered with ClinicalTrials.gov, number NCT00140673 (eTrack444563-023). FINDINGS: 897 infants were excluded from the according-to-protocol analysis. Fewer cases (p<0.0001) of severe rotavirus gastroenteritis were recorded for the combined 2-year period in the RIX4414 group (32 [0.4%] of 7205; 95% CI 0.3-0.6) than in the placebo group (161 [2.3%] of 7081; 1.9-2.6), resulting in a vaccine efficacy of 80.5% (71.3-87.1) to 82.1% (64.6-91.9) against wild-type G1, 77.5% (64.7-86.2) against pooled non-G1 strains, and 80.5% (67.9-88.8) against pooled non-G1 P[8] strains. Vaccine efficacy for hospital admission for rotavirus gastroenteritis was 83.0% (73.1-89.7) and for admission for diarrhoea of any cause was 39.3% (29.1-48.1). No cases of intussusception were reported during the second year of follow-up. INTERPRETATION: Two doses of RIX4414 were effective against severe rotavirus gastroenteritis during the first 2 years of life in a Latin American setting. Inclusion of RIX4414 in routine paediatric immunisations should reduce the burden of rotavirus gastroenteritis worldwide.

Safety and efficacy of an attenuated vaccine against severe rotavirus gastroenteritis.

BACKGROUND: The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial. METHODS: We studied 63,225 healthy infants from 11 Latin American countries and Finland who received two oral doses of either the HRV vaccine (31,673 infants) or placebo (31,552 infants) at approximately two months and four months of age. Severe gastroenteritis episodes were identified by active surveillance. The severity of disease was graded with the use of the 20-point Vesikari scale. Vaccine efficacy was evaluated in a subgroup of 20,169 infants (10,159 vaccinees and 10,010 placebo recipients). RESULTS: The efficacy of the vaccine against severe rotavirus gastroenteritis and against rotavirus-associated hospitalization was 85 percent (P<0.001 for the comparison with placebo) and reached 100 percent against more severe rotavirus gastroenteritis. Hospitalization for diarrhea of any cause was reduced by 42 percent (95 percent confidence interval, 29 to 53 percent; P<0.001). During the 31-day window after each dose, six vaccine recipients and seven placebo recipients had definite intussusception (difference in risk, -0.32 per 10,000 infants; 95 percent confidence interval, -2.91 to 2.18; P=0.78). CONCLUSIONS: Two oral doses of the live attenuated G1P[8] HRV vaccine were highly efficacious in protecting infants against severe rotavirus gastroenteritis, significantly reduced the rate of severe gastroenteritis from any cause, and were not associated with an increased risk of intussusception. (ClinicalTrials.gov numbers, NCT00139347 and NCT00263666.)

Live attenuated human rotavirus vaccine, RIX4414, provides clinical protection in infants against rotavirus strains with and without shared G and P genotypes: integrated analysis of randomized controlled trials.

BACKGROUND: : The 2-dose, oral live attenuated human G1P[8] rotavirus vaccine (RIX4414) is highly effective against rotavirus gastroenteritis caused by circulating G1 and non-G1 types. An integrated analysis on vaccine efficacy was undertaken to obtain more precise estimates of the overall protective effect of the RIX4414 vaccine against rotavirus gastroenteritis due to common rotavirus types (G1, G3, G4, G9, P[8]) and less commonly encountered strains such as G2P[4] across heterogenous settings. METHODS: : The studies used in the integrated analysis were all previously reported randomized, double-blind, placebo-controlled, phase II and III trials with at least 1 report of rotavirus gastroenteritis in the efficacy follow-up period (up to 1 year of age or end of first RV epidemic season after vaccination). The integrated analysis was performed for all circulating rotavirus strains sharing G and/or P genotype and not sharing G or P genotype with the vaccine strain. Vaccine efficacy was estimated as 1 minus rate of rotavirus gastroenteritis relative to placebo, using exact Poisson rate ratio stratified by study. RESULTS: : The integrated estimates for vaccine efficacy against severe rotavirus gastroenteritis were 87.43% (95% confidence interval [CI]: 78.89-92.86) for G1P[8] strains, 71.42% (95% CI: 20.12-91.11) for G2P[4] strains, 90.19% (95% CI: 55.51-98.94) for G3P[8] strains, 93.37% (95% CI: 51.50-99.85) for G4P[8] strains, and 83.76% (95% CI: 71.18-91.28) for G9P[8] strains. The integrated estimates for vaccine efficacies against rotavirus gastroenteritis of any severity were 82.57% (95% CI: 73.91-88.56) for G1P[8] strains, 81.04% (95% CI: 31.58-95.76) for G2P[4] strains, 87.66% (95% CI: 34.57-98.76) for G3P[8] strains, 84.86% (95% CI: 50.92-96.41) for G4P[8] strains, and 60.64% (95% CI: 38.15-74.96) for G9P[8] strains. CONCLUSIONS: : Two doses of RIX4414 provide overall good clinical protection against all cases of rotavirus gastroenteritis and comparable, high clinical protection against severe rotavirus gastroenteritis caused by circulating rotavirus strains with and without G and P genotypes shared with the vaccine strain, such as G2P[4].

Phase I/II Trial of Liver-derived Mesenchymal Stem Cells in Pediatric Liver-based Metabolic Disorders: A Prospective, Open Label, Multicenter, Partially Randomized, Safety Study of One Cycle of Heterologous Human Adult Liver-derived Progenitor Cells (HepaStem) in Urea Cycle Disorders and Crigler-Najjar Syndrome Patients.

BACKGROUND: Regenerative medicine using stem cell technology is an emerging field that is currently tested for inborn and acquired liver diseases. OBJECTIVE: This phase I/II prospective, open label, multicenter, randomized trial aimed primarily at evaluating the safety of Heterologous Human Adult Liver-derived Progenitor Cells (HepaStem) in pediatric patients with urea cycle disorders (UCDs) or Crigler-Najjar (CN) syndrome 6 months posttransplantation. The secondary objective included the assessment of safety up to 12 months postinfusion and of preliminary efficacy. METHODS: Fourteen patients with UCDs and 6 with CN syndrome were divided into 3 cohorts by body weight and intraportally infused with 3 doses of HepaStem. Clinical status, portal vein hemodynamics, morphology of the liver, de novo detection of circulating anti-human leukocyte antigen antibodies, and clinically significant adverse events (AEs) and serious adverse events to infusion were evaluated by using an intent-to-treat analysis. RESULTS: The overall safety of HepaStem was confirmed. For the entire study period, patient-month incidence rate was 1.76 for the AEs and 0.21 for the serious adverse events, of which 38% occurred within 1 month postinfusion. There was a trend of higher events in UCD as compared with CN patients. Segmental left portal vein thrombosis occurred in 1 patient and intraluminal local transient thrombus in a second patient. The other AEs were in line with expectations for catheter placement, cell infusion, concomitant medications, age, and underlying diseases. CONCLUSIONS: This study led to European clinical trial authorization for a phase II study in a homogeneous patient cohort, with repeated infusions and intermediate doses.

Evaluation of circulating intestinally committed memory B cells in children vaccinated with attenuated human rotavirus vaccine.

In a double blind trial, 319 fully immunized children received two doses of either placebo or 10(6.7) focus-forming units of the attenuated RIX4414 human rotavirus (RV) vaccine ("all-in-one" formulation). Plasma RV-specific IgA (RV IgA), stool RV IgA, and circulating total and RV memory B cells (CD19+ IgD+/- CD27+) with an intestinal homing phenotype (alpha4beta7+ CCR9+/-) were measured, after the first and second doses, as potential correlates of protection. After the first and/or second dose, 54% of vaccinees and 13% of placebo recipients had plasma RV IgA. Before vaccination, most (95%) of the children (of both study groups) were breast-fed and had stool RV IgA (68.64%). Coproconversion (4-fold increase) after the first and/or second dose was observed in 32.7% of vaccinees and 17.4% of placebo recipients. No significant difference was seen when comparing the frequencies of any subset of memory B cells between vaccinees and placebo recipients. Statistically significant weak correlations were found between plasma RV IgA titers and coproconversion, and several subsets of memory B cells. The vaccine provided 74.8% protection (95% confidence interval, 30.93-92.62) against any RV gastroenteritis and 100% protection (95% confidence interval, 14.53-100) against severe RV gastroenteritis. When vaccinees and placebo recipients were considered together, a correlation was found between protection from disease and plasma RV IgA measured after dose 2 and RV memory (IgD- CD27+ alpha4beta7+ CCR9+) circulating B cells measured after dose 1. However, the correlation coefficients for both tests were low (<0.2), suggesting that other factors are important in explaining protection from disease.

Intussusception among young children in Europe.

Intussusception, a potentially lethal condition with poorly understood etiology, is the most common cause of acute intestinal obstruction in children younger than 5 years old. In some cases, the condition has been associated with administration of the first licensed rotavirus vaccine, the reassortant rhesus-human tetravalent rotavirus vaccine (RRV-TV; RotaShield). No such association has to date been reported from large phase III safety trials with new rotavirus vaccines. As 2 new, live-attenuated oral rotavirus vaccines are currently under review for approval by the European Union regulatory authorities, a review of the clinical, etiologic and epidemiologic aspects of intussusception in Europe is urgently needed. We conducted a review of Medline literature, published from 1995 onwards on intussusception in the World Health Organization's European Region. The results are compared with data from previous reviews and other regions. The classic triad of intussusception symptoms (abdominal pain, abdominal mass, bloody stools) was present in 29-33% of patients according to the medical literature reviewed. Conservative treatment (barium, air or saline enema) was the rule (81% of cases), and few complications were observed during treatment. Treatment outcome was generally favorable, with recurrence occurring in approximately 1 in 10 patients, and only 1 death reported. Structural lead points were seen in 3% of patients; no other reliable data on the etiology of intussusception were found. The incidence of acute intussusception in young children in Europe, according to 6 heterogeneous hospital-based studies, ranged from 0.66 to 2.24 per 1000 children in inpatient departments and from 0.75 to 1.00 per 1000 children in emergency departments. Peak incidences were found in children 3-9 months of age. There are still gaps in our knowledge of intussusception with respect to its etiology and especially by which mechanisms RRV-TV might have caused it to occur. Data from regions outside Europe showed that rotavirus infection and disease are not associated with intussusception. As new rotavirus vaccines become available for use in Europe, postlicensure surveillance for intussusception is indicated and may be instrumental in further understanding the epidemiology of this condition and in further assessing the safety of future vaccines.

Comparative evaluation of safety and immunogenicity of two dosages of an oral live attenuated human rotavirus vaccine.

BACKGROUND: Rotavirus is a major cause of gastroenteritis in children worldwide and is estimated to be responsible for more than 500,000 physician visits, 50,000 hospitalizations and 20 deaths in the United States each year. OBJECTIVE: To compare the safety and immunogenicity of 2 dosages of a live attenuated oral monovalent G1 human rotavirus (HRV) vaccine in healthy infants. DESIGN/METHODS: In this randomized, double blind trial conducted in the United States and Canada, 529 healthy infants 5-15 weeks of age received HRV vaccine containing either 10 or 10 focus-forming units or placebo. Two doses were administered orally at a 2-month interval concomitantly with routine childhood vaccines. Symptoms of fever, irritability/fussiness, diarrhea, vomiting, loss of appetite and cough/runny nose were solicited for 15 days postvaccination, nonserious adverse events for 43 days postvaccination and serious adverse events throughout the study. Vaccine take was defined as appearance of serum antirotavirus IgA in postimmunization sera at a titer of > or =20 units/mL or vaccine virus shedding in any stool sample collected between the first dose and 2 months after the second dose. RESULTS: No serious adverse events considered related to vaccine were reported. The incidence of solicited symptoms was similar among treatment groups during the 15-day postvaccination surveillance periods. No significant difference in vaccine take after 2 doses (88.0% in high dose group and 81.5% in low dose group) was seen between vaccine groups (P = 0.153). CONCLUSIONS: Two doses of either dosage level of HRV vaccine administered concurrently with routine childhood vaccines to healthy infants 5-15 weeks of age were well-tolerated and were highly immunogenic.

Evaluation of safety, immunogenicity and efficacy of an attenuated rotavirus vaccine, RIX4414: A randomized, placebo-controlled trial in Latin American infants.

BACKGROUND: A live attenuated monovalent rotavirus vaccine RIX4414 was developed with a human strain of G1P1A P[8] specificity to reduce the rotavirus burden in children. METHODS: A double blind, randomized, placebo-controlled study evaluated the efficacy, immunogenicity, safety and reactogenicity of 2 oral doses of RIX4414 (10(4.7), 10(5.2) or 10(5.8) focus-forming units) at 2 and 4 months coadministered with routine vaccinations and oral poliovirus vaccine given for study purposes at least 14 days apart. The 2155 infants (1618 vaccine/537 placebo) enrolled in Brazil, Mexico and Venezuela were followed until 1 year of age. RESULTS: Antirotavirus IgA seroconversion rates 2 months after dose 2 ranged between 61% (10(4.7) ffu group) and 65% (10(5.8) ffu group), and most of the infants had seroprotective levels of antibodies to coadministered routine vaccinations. The reactogenicity profile of RIX4414 was similar to that of the placebo, and no vaccination-related serious adverse events were reported. Protective efficacy against severe and any rotavirus gastroenteritis from 15 days post-dose 2 was highest in the 10(5.8) ffu group [86%; 95% confidence interval (95% CI), 63-96% and 70% (95% CI 46-84%), P < 0.001, 2-sided Fisher's exact test]. The efficacy against hospitalization was 79% (95% CI 48-92%) for pooled vaccine groups. Multiple rotavirus serotypes [G1 (50%), G9 (40%), G2, G3 and G4] were identified from gastroenteritis stools (enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction) during the study period. For severe gastroenteritis caused by G9 serotypes, the protection reached 77% (95% CI 18-96%) in the 10(5.8) ffu group, providing proof of concept that the monovalent G1P1A P[8] human rotavirus vaccine elicits cross-protection against the G9 strain. A reduction in any and severe rotavirus gastroenteritis was already observed at post-dose 1 (period: day of dose 1 to 14 days post-dose 2) in vaccinees compared with placebo recipients. CONCLUSIONS: Two doses of RIX4414 are highly efficacious, providing cross-protection (G1 and G9 strains, prevalent during this study) and early protection against any and severe rotavirus gastroenteritis and hospitalization to infants in Latin America.

Efficacy of RIX4414 live attenuated human rotavirus vaccine in Finnish infants.

BACKGROUND: Rotavirus gastroenteritis, a major cause of mortality and morbidity worldwide, is a vaccine-preventable disease. New safe and effective candidate rotavirus vaccines are needed to replace the withdrawn rhesus rotavirus-based oral vaccine. METHODS: We evaluated a monovalent human rotavirus vaccine, serotype G1, strain RIX4414, for efficacy, immunogenicity and safety in a randomized, double blind, placebo-controlled trial in Finland. We randomly allocated 405 healthy infants to receive 2 doses of vaccine or placebo (ratio 2:1) at approximately 2 and 4 months of age. The infants were followed during 2 rotavirus epidemic seasons (2000-2002) for acute gastroenteritis. Rotaviruses in diarrheal stool samples were primarily detected by enzyme-linked immunosorbent assay and confirmed and G-typed by reverse transciption-polymerase chain reaction. RESULTS: The vaccine was well-tolerated. No vaccine-related serious adverse events were observed during the study period. Rotavirus IgA (enzyme-linked immunosorbent assay) seroconversion rate was 80% after 2 doses. Thirty-eight cases of rotavirus gastroenteritis were detected during the entire follow-up period; 35 of these were of the G1 type. RIX4414 vaccine significantly decreased the occurrence of any rotavirus compared with placebo. Efficacy during the first rotavirus epidemic season was 73% [95% confidence interval (95% CI), 27-91%] and 90% (95% CI 10-100%) against any and severe rotavirus gastroenteritis, respectively, and during the entire follow-up period 72% (95% CI 42-87%) against any and 85% (95% CI 42-97%) against severe rotavirus gastroenteritis (P < 0.05 for all comparisons). CONCLUSIONS: RIX4414 strain of G1 human rotavirus vaccine was well-tolerated, immunogenic and efficacious in infants against rotavirus gastroenteritis during a 2-year period. To further increase vaccine "take" and efficacy, a higher dose of this vaccine may be considered for future efficacy trials.

A rotavirus vaccine for prophylaxis of infants against rotavirus gastroenteritis.

The need for safe and effective vaccines to reduce morbidity and mortality caused by rotavirus gastroenteritis in children is well-known. A live attenuated monovalent rotavirus vaccine (Rotarix) containing human rotavirus strain RIX4414 of G1P1A P[8] specificity is being developed to meet the global need. An overview of RIX4414 trials in developed and developing settings is presented for 3 selected trials conducted in Finland (pilot study), Latin America (Brazil, Mexico and Venezuela) and Singapore involving 5024 infants. The vaccine was well-tolerated, with no increase in any solicited symptoms as compared with the placebo. After 2 doses, 61-91% of vaccinated infants developed rotavirus-specific IgA antibodies. There was no interference with immunogenicity of coadministered routine pediatric vaccines. Rotarix significantly reduced rotavirus gastroenteritis episodes and rotavirus-related hospitalizations in vaccinated infants compared with placebo recipients (P < 0.05). Vaccine efficacy was observed against severe rotavirus gastroenteritis caused by G1 and non-G1 types including the emerging G9 type (P < 0.05) in Latin America. These results show prospects for widespread use of Rotarix to reduce rotavirus disease burden and warrant continued worldwide evaluation.

Safety, Reactogenicity, and Immunogenicity of Human Rotavirus Vaccine RIX4414 in Human Immunodeficiency Virus-positive Infants in South Africa.

BACKGROUND: rotavirus and human immunodeficiency virus (HIV) infections are a cause of great public health concern in developing countries. The current study evaluated the safety, reactogenicity, and immunogenicity of RIX4414 vaccine in asymptomatic or mildly symptomatic (clinical stages I and II according to WHO classification) HIV-infected South African infants. METHODS: a total of 100 HIV-positive infants aged 6 to 10 weeks enrolled in this double-blind, 1:1 randomized, placebo-controlled study were allocated into 2 groups to receive 3 doses of RIX4414 vaccine/placebo according to a 0-, 1-, and 2-month schedule. Routine vaccines were concomitantly administered. Solicited and unsolicited symptoms were recorded for 15 and 31 days after each dose, respectively. Serious adverse events were recorded throughout the study period. Serum antirotavirus IgA concentrations (enzyme-linked immunosorbent assay, cut-off ≥ 20 U/mL) and the immunodeficiency status were determined at screening and 2 months post-Dose 3. Stool samples were analyzed for rotavirus using enzyme-linked immunosorbent assay at predetermined points and during diarrhea episodes. RESULTS: all symptoms (solicited and unsolicited) occurred at a similar frequency in both groups. Six fatal serious adverse events in RIX4414 and 9 in placebo groups were reported. At 2 months post-Dose 3, the seroconversion rates were 57.1% (95% CI: 34-78.2) in RIX4414 and 18.2% (95% CI: 5.2-40.3) in the placebo group. The mean absolute CD4 cell count, CD4 percentage, and HIV-1 viral load were comparable in both groups at screening and 2 months post-Dose 3. Rotavirus shedding peaked at Day 7 after Dose 1 of RIX4414 with prolonged shedding was observed in 1 infant only. CONCLUSIONS: : Three doses of RIX4414 vaccine was tolerated well by the South African HIV-positive infants. A satisfactory immune response was mounted without aggravating their immunologic or HIV condition.

Evaluation of RIX4414, a live, attenuated rotavirus vaccine, in a randomized, double-blind, placebo-controlled phase 2 trial involving 2464 Singaporean infants.

BACKGROUND: At present, no rotavirus vaccine is commercially available for use worldwide. Hence, a live, attenuated monovalent vaccine was developed with human strain RIX4414 (G1P1A P[8] specificity). Vaccination trials involving infants are ongoing in developed and developing countries. METHODS: This study was a randomized, double-blind, placebo-controlled trial conducted at pediatric hospitals and polyclinics in Singapore for the evaluation of the immunogenicity, reactogenicity, and efficacy of 2 oral doses of RIX4414. In total, 2464 healthy infants (who were 11-17 weeks old when the first dose was administered, which is in accordance with the local immunization schedule) were enrolled to receive RIX4414 at 3 concentrations of virus (10(4.7), 10(5.2), or 10(6.1) focus-forming units) or placebo at 1-month intervals, concomitantly with routinely administered infant vaccines. RESULTS: The RIX4414 vaccine was highly immunogenic, and virtually all vaccine recipients (98%-100%) experienced "vaccine take" (i.e., a combined immunogenicity end point based on seroconversion and/or shedding of RIX4414 in postvaccination stool samples) after receipt of 2 doses at all 3 dosage levels. Depending on the virus concentration, the anti-rotavirus IgA seroconversion rate varied from 76% (95% confidence interval [CI], 68%-83%) to 91% (95% CI, 85%-95%). Two doses of RIX4414 were well tolerated, with no increase in high fever, severe diarrhea, or vomiting after either dose or with increased viral concentration, compared with placebo. There was no observed interference with routine vaccinations of infants when RIX4414 was coadministered. The calculated efficacy of RIX4414 against rotavirus gastroenteritis was 82% (P = .046); however, this result was considered to be of limited conclusive value because of the low number of rotavirus gastroenteritis episodes identified during the follow-up period. CONCLUSIONS: The live, attenuated rotavirus vaccine (RIX4414) was well tolerated and highly immunogenic in Singaporean infants. The immunogenicity of routinely administered infant vaccines was not impaired by concomitant administration of RIX4414 vaccine.