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Rotavirus is a major cause of death and complications in infants, especially in sub-Saharan Africa. In this randomized clinical trial in Niger, a low-cost, heat-stable rotavirus vaccine was shown to have nearly 70% efficacy against severe rotavirus gastroenteritis. Rotavirus is a leading cause of severe gastroenteritis among young children and is responsible for approximately 37% of deaths from diarrhea among children younger than 5 years of age worldwide. 1 , 2 Two live, oral, attenuated rotavirus vaccines (Rotarix, GlaxoSmithKline, and RotaTeq, Merck) have met the prequalification requirements of the World Health Organization (WHO), stipulations that allow for purchase by United Nations agencies. 3 The efficacy of these vaccines has been shown, with an important effect on hospital admissions and mortality. 4 – 14 Sub-Saharan Africa has the highest rate of death associated with rotavirus disease, 1 but vaccination on a large scale presents challenges. . . .

A strategy of administering a neonatal rotavirus vaccine at birth to target early prevention of rotavirus gastroenteritis may address some of the barriers to global implementation of a rotavirus vaccine. We conducted a randomized, double-blind, placebo-controlled trial in Indonesia to evaluate the efficacy of an oral human neonatal rotavirus vaccine (RV3-BB) in preventing rotavirus gastroenteritis. Healthy newborns received three doses of RV3-BB, administered according to a neonatal schedule (0 to 5 days, 8 weeks, and 14 weeks of age) or an infant schedule (8 weeks, 14 weeks, and 18 weeks of age), or placebo. The primary analysis was conducted in the per-protocol population, which included only participants who received all four doses of vaccine or placebo within the visit windows, with secondary analyses performed in the intention-to-treat population, which included all participants who underwent randomization. Among the 1513 participants in the per-protocol population, severe rotavirus gastroenteritis occurred up to the age of 18 months in 5.6% of the participants in the placebo group (28 of 504 babies), in 1.4% in the neonatal-schedule vaccine group (7 of 498), and in 2.7% in the infant-schedule vaccine group (14 of 511). This resulted in a vaccine efficacy of 75% (95% confidence interval [CI], 44 to 91) in the neonatal-schedule group (P<0.001), 51% (95% CI, 7 to 76) in the infant-schedule group (P=0.03), and 63% (95% CI, 34 to 80) in the neonatal-schedule and infant-schedule groups combined (combined vaccine group) (P<0.001). Similar results were observed in the intention-to-treat analysis (1649 participants); the vaccine efficacy was 68% (95% CI, 35 to 86) in the neonatal-schedule group (P=0.001), 52% (95% CI, 11 to 76) in the infant-schedule group (P=0.02), and 60% (95% CI, 31 to 76) in the combined vaccine group (P<0.001). Vaccine response, as evidenced by serum immune response or shedding of RV3-BB in the stool, occurred in 78 of 83 participants (94%) in the neonatal-schedule group and in 83 of 84 participants (99%) in the infant-schedule group. The incidence of adverse events was similar across the groups. No episodes of intussusception occurred within the 21-day risk period after administration of any dose of vaccine or placebo, and one episode of intussusception occurred 114 days after the third dose of vaccine in the infant-schedule group. RV3-BB was efficacious in preventing severe rotavirus gastroenteritis when administered according to a neonatal or an infant schedule in Indonesia. (Funded by the Bill and Melinda Gates Foundation and others; Australian New Zealand Clinical Trials Registry number, ACTRN12612001282875 .).

Background. Noroviruses are the most common cause of gastroenteritis in the United States. An understanding of the infectious dose of these viruses is important for risk assessment studies. Methods. Healthy adults were enrolled in a randomized, double-blind, placebo-controlled evaluation of different dosages of Norwalk virus. Eligible subjects were monitored for clinical gastroenteritis, and infection status was determined. The presence of virus in vomitus was also assessed. Results. Fifty-seven persons were enrolled; 8 received placebo and an additional 8 persons were considered to be nonsusceptible on the basis of being secretor negative. Twenty-one persons were infected (all blood group O or A), and 67% of those infected developed viral gastroenteritis. The 50% human infectious dose was calculated to be 3.3 reverse transcription polymerase chain reaction units (approximately 1320 genomic equivalents [gEq]) for secretorpositive blood group O or A persons and 7.0 (approximately 2800 gEq) for all secretor-positive persons. The time of illness onset was inversely correlated with inoculum dose. The maximal concentration of virus shedding was higher for persons with gastroenteritis. Norwalk virus was identified in 15 of 27 (56%) vomitus samples at a median concentration of 41000 gEq/mL. Conclusions. The 50% human infectious dose measured is higher than previous estimates and similar to that of other RNA viruses. Clinical TriaU Registration. NCT00138476.

Human noroviruses (NoVs) are the primary cause of acute gastroenteritis and are characterized by antigenic variation between genogroups and genotypes and antigenic drift of strains within the predominant GII.4 genotype. In the context of this diversity, an effective NoV vaccine must elicit broadly protective immunity. We used an antibody (Ab) binding blockade assay to measure the potential cross-strain protection provided by a multivalent NoV virus-like particle (VLP) candidate vaccine in human volunteers. Sera from ten human volunteers immunized with a multivalent NoV VLP vaccine (genotypes GI.1/GII.4) were analyzed for IgG and Ab blockade of VLP interaction with carbohydrate ligand, a potential correlate of protective immunity to NoV infection and illness. Immunization resulted in rapid rises in IgG and blockade Ab titers against both vaccine components and additional VLPs representing diverse strains and genotypes not represented in the vaccine. Importantly, vaccination induced blockade Ab to two novel GII.4 strains not in circulation at the time of vaccination or sample collection. GII.4 cross-reactive blockade Ab titers were more potent than responses against non-GII.4 VLPs, suggesting that previous exposure history to this dominant circulating genotype may impact the vaccine Ab response. Further, antigenic cartography indicated that vaccination preferentially activated preexisting Ab responses to epitopes associated with GII.4.1997. Study interpretations may be limited by the relevance of the surrogate neutralization assay and the number of immunized participants evaluated. Vaccination with a multivalent NoV VLP vaccine induces a broadly blocking Ab response to multiple epitopes within vaccine and non-vaccine NoV strains and to novel antigenic variants not yet circulating at the time of vaccination. These data reveal new information about complex NoV immune responses to both natural exposure and to vaccination, and support the potential feasibility of an efficacious multivalent NoV VLP vaccine for future use in human populations. ClinicalTrials.gov NCT01168401.

Rotavirus is the leading cause of gastroenteritis in children worldwide. In this report, the efficacy of the rotavirus vaccine among 4417 children in Malawi and South Africa was studied in a randomized trial. Severe rotavirus gastroenteritis occurred in 4.9% of the infants in the placebo group as compared with 1.9% of the infants in the pooled vaccine group; the vaccine efficacy was 61.2%. In this trial of rotavirus vaccine in Malawi and South Africa, severe rotavirus gastroenteritis occurred in 4.9% of the infants in the placebo group as compared with 1.9% of the infants in the pooled vaccine group; the vaccine efficacy was 61.2%. Rotavirus is the most important cause of severe gastroenteritis among children worldwide. The World Health Organization (WHO) estimates that globally 527,000 deaths occur each year among children as a result of rotavirus infection 1 ; more than 230,000 of the deaths occur in sub-Saharan Africa. Six of the seven countries with the highest mortality due to rotavirus diarrhea are located in Africa. 2 Similarly, data generated from global rotavirus surveillance networks highlight the burden of hospitalizations for rotavirus 3 ; among young children hospitalized for acute diarrhea, the median detection rate for rotavirus was 40% globally and 41% in Africa. Therefore, measures to . . .

Gastroenteritis accounts for nearly 500,000 deaths in children younger than 5 years annually. Although probiotics have been touted as having the potential to expedite diarrhea resolution, recent clinical trials question their effectiveness. A potential explanation is a shift in pathogens following the introduction of a rotavirus vaccine. Here, we report the results of a multi-center, double-blind trial of 816 children with acute gastroenteritis who completed follow-up and provided multiple stool specimens. Participants were randomized to receive a probiotic containing Lactobacillus rhamnosus and Lactobacillus helveticus or placebo. We report no virus-specific beneficial effects attributable to the probiotic, either in reducing clinical symptoms or viral nucleic acid clearance from stool specimens collected up to 28 days following enrollment. We provide pathophysiological and microbiologic evidence to support the clinical findings and conclude that our data do not support routine probiotic administration to children with acute gastroenteritis, regardless of the infecting virus. Here, the authors report the results of a randomized, placebo controlled trial of children with acute gastroenteritis who were treated with a probiotic and find no virus-specific beneficial effects attributable to the probiotic, either in reducing clinical symptoms or clearance of viral nucleic acid from stool specimens.

We aimed to assess the efficacy of the oral live attenuated human rotavirus vaccine Rotarix (RIX4414) for prevention of rotavirus gastroenteritis in European infants during their first 2 years of life. 3994 study participants were enrolled from six countries and were randomly assigned two oral doses of either RIX4414 (n=2646) or placebo (n=1348), which were coadministered with the first two doses of specific childhood vaccinations. Follow-up for gastroenteritis episodes was undertaken from 2 weeks post-dose two through the two consecutive rotavirus seasons following vaccinations (combined efficacy follow-up period; mean duration 17 months [SD 1·6]). Our primary endpoint was vaccine efficacy against rotavirus gastroenteritis of any severity during the first efficacy follow-up period (2 weeks post-dose two to the end of the first rotavirus season). Stool specimens obtained during gastroenteritis episodes were tested for rotavirus by ELISA and typed by RT-PCR. Episodes scoring 11 or greater on the 20-point Vesikari scale were classified as severe. Analysis was according to protocol. This study is registered with ClinicalTrials.gov, number NCT00140686 (eTrack102247). 120 infants were excluded from the according-to-protocol analysis. During the first efficacy follow-up period (mean duration 5·7 months [SD 1·2]), 24 of 2572 infants allocated RIX4414 versus 94 of 1302 given placebo had rotavirus gastroenteritis episodes of any severity, resulting in a vaccine efficacy of 87·1% (95% CI 79·6–92·1; p<0·0001). For the combined efficacy follow-up period, vaccine efficacy against severe rotavirus gastroenteritis was 90·4% (85·1–94·1; p<0·0001), for admission owing to rotavirus gastroenteritis 96·0% (83·8–99·5; p<0·0001), and for rotavirus-related medical attention 83·8% (76·8–88·9; p<0.0001), and significant protection against severe rotavirus gastroenteritis by circulating G1, G2, G3, G4, and G9 rotavirus types was shown. In a European setting, two doses of RIX4414 coadministered with childhood vaccines provided high protection against any and severe rotavirus gastroenteritis, with an overall reduction of admissions for gastroenteritis over two consecutive rotavirus epidemic seasons.

In this double-blind trial, two oral doses of a live attenuated G1P[8] rotavirus vaccine were highly efficacious in protecting infants against severe diarrheal disease. During the active surveillance of 63,225 infants, the risk of intussusception was no greater after vaccination than it was with placebo (six cases vs. seven cases). In this double-blind trial, two oral doses of a live attenuated G1P[8] rotavirus vaccine were highly efficacious in protecting infants against severe diarrheal disease. Rotavirus is the leading recognized cause of diarrhea-related illness and death among infants and young children. 1 – 5 Every year, rotavirus is associated with 25 million clinic visits, 2 million hospitalizations, and more than 600,000 deaths worldwide among children younger than five years of age. 6 , 7 Development of a safe and effective rotavirus vaccine is therefore a high priority, particularly but not exclusively in developing countries, where the burden of disease is highest. 8 , 9 Since the withdrawal from the market of the tetravalent rhesus–human reassortant vaccine (RotaShield, Wyeth Laboratories) because of an association with intussusception, 10 , 11 ruling out such a risk . . .

In this randomized trial, the clinical efficacy of an oral, live pentavalent human–bovine reassortant vaccine was estimated to be 98.0 percent against severe gastroenteritis due to rotavirus. In the safety study, which included 68,038 infants, the rates of intussusception were similar in the vaccine and placebo groups (relative risk, 0.8; 95 percent confidence interval, 0.3 to 1.8). In this randomized trial, the clinical efficacy of an oral, live pentavalent human–bovine reassortant vaccine was estimated to be 98.0 percent against severe gastroenteritis due to rotavirus. Rotavirus is the leading cause of hospitalization and death from acute gastroenteritis among infants and young children worldwide. More than 2 million hospitalizations and nearly half a million deaths are attributed to this infection annually. 1 , 2 The strategy of preventing rotavirus through vaccination derives from studies demonstrating that wild-type rotavirus infection induces immunity against subsequent rotavirus gastroenteritis. 3 – 6 Primary rotavirus infection provides substantial protection against gastroenteritis caused by the same serotype and against severe disease regardless of serotype. The four most prevalent serotypes, which account for more than 80 percent of cases of human rotavirus disease worldwide, are G1P[8], G2P[4], . . .

Background. Noroviruses cause significant morbidity and mortality from acute gastroenteritis in all age groups worldwide. Methods.We conducted 2 phase 1 double-blind, controlled studies of a virus-like particle (VLP) vaccine derived from norovirus GI.1 genotype adjuvanted with monophosphoryl lipid A (MPL) and the mucoadherent chitosan. Healthy subjects 18–49 years of age were randomized to 2 doses of intranasal Norwalk VLP vaccine or controls 21 days apart. Study 1 evaluated 5-, 15-, and 50-μg dosages of Norwalk antigen, and study 2 evaluated 50-and 100-μg dosages. Volunteers recorded symptoms for 7 days after dosing, and safety was followed up for 180 days. Blood samples were collected for serological profile, antibody secreting cells (ASCs), and analysis of ASC homing receptors. Results. The most common symptoms were nasal stuffiness, discharge, and sneezing. No vaccine-related serious adverse events occurred. Norwalk VLP-specific immunoglobulin G and immunoglobulin A antibodies increased 4.8-and 9.1-fold, respectively, for the 100-μg dosage level. All subjects tested who received the 50-or 100-μg vaccine dose developed immunoglobulin A ASCs. These cells expressed molecules associated with homing to mucosal and peripheral lymphoid tissues. Conclusions. The intranasal monovalent adjuvanted Norwalk VLP vaccine was well tolerated and highly immunogenic and is a candidate for additional study. Trial Registration. ClinicalTrials.gov identifier: NCT00806962.