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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 . . .

► Human rotavirus vaccine reduced severe diarrhoea by half in a trial in Malawi. ► There was a substantial reduction of vaccine efficacy in the second year of life. ► Three vaccine doses may give more sustained protection compared with two doses. ► Routine rotavirus vaccination in Malawi will give significant public health benefit. ► The optimum rotavirus vaccine dosing schedule requires further investigation. Rotavirus gastroenteritis is a major cause of morbidity and mortality among African infants and young children. A phase III, placebo-controlled, multi-centre clinical trial of a live, oral G1P[8] human rotavirus vaccine (RIX4414) undertaken in Malawi and South Africa significantly reduced the incidence of severe rotavirus gastroenteritis in the first year of life. We now report on vaccine efficacy in the Malawi cohort of children who were followed into the second year of life. A total of 1773 healthy infants were enrolled in Blantyre, Malawi into three groups. Two groups received three doses of RIX4414 or placebo at age 6, 10, and 14 weeks and the third group received placebo at 6 weeks and RIX4414 at age 10 and 14 weeks. Subjects were followed by weekly home visits for episodes of gastroenteritis until 1 year of age, and were then re-consented for further follow-up to 18–24 months of age. Severity of gastroenteritis episodes was graded according to the Vesikari scoring system. Seroconversion for anti-rotavirus IgA was determined on a subset of children by using ELISA on pre- and post-vaccine blood samples. Rotavirus VP7 (G) and VP4 (P) genotypes were determined by RT-PCR. A total of 70/1030 (6.8%, 95% CI 5.3–8.5) subjects in the pooled (2 dose plus 3 dose) RIX4414 group compared with 53/483 (11.0%, 8.3–14.1) subjects in the placebo group developed severe rotavirus gastroenteritis in the entire follow-up period (vaccine efficacy 38.1% (9.8–57.3)). The point estimate of efficacy in the second year of life (17.6%; −59.2 to 56.0) was lower than in the first year of life (49.4%; 19.2–68.3). There were non-significant trends towards a higher efficacy in the second year of life among children who received the three-dose schedule compared with the two-dose schedule, and a higher anti-rotavirus IgA seroresponse rate in the three-dose RIX4414 group. Rotavirus strains detected included genotype G12 (31%); G9 (23%); and G8 (18%); only 18% of strains belonged to the G1P[8] genotype. While the optimal dosing schedule of RIX4414 in African infants requires further investigation, vaccination with RIX4414 significantly reduced the incidence of severe gastroenteritis caused by diverse rotavirus strains in an impoverished African population with high rotavirus disease burden in the first two years of life.

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], . . .

Despite the success of rotavirus vaccines, suboptimal vaccine efficacy in regions with a high burden of disease continues to present a challenge to worldwide implementation. A birth dose strategy with a vaccine developed from an asymptomatic neonatal rotavirus strain has the potential to address this challenge and provide protection from severe rotavirus disease from birth. This phase 2a randomised, double-blind, three-arm, placebo-controlled safety and immunogenicity trial was undertaken at a single centre in New Zealand between Jan 13, 2012, and April 17, 2014. Healthy, full-term (≥36 weeks gestation) babies, who weighed at least 2500 g, and were 0–5 days old at the time of randomisation were randomly assigned (1:1:1; computer-generated; telephone central allocation) according to a concealed block randomisation schedule to oral RV3-BB vaccine with the first dose given at 0–5 days after birth (neonatal schedule), to vaccine with the first dose given at about 8 weeks after birth (infant schedule), or to placebo. The primary endpoint was cumulative vaccine take (serum immune response or stool shedding of vaccine virus after any dose) after three doses. The immunogenicity analysis included all randomised participants with available outcome data. This trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611001212943. 95 eligible participants were randomised, of whom 89 were included in the primary analysis. A cumulative vaccine take was detected in 27 (90%) of 30 participants in the neonatal schedule group after three doses of RV3-BB vaccine compared with four (13%) of 32 participants in the placebo group (difference in proportions 0·78, 95% CI 0·55–0·88; p<0·0001). 25 (93%) of 27 participants in the infant schedule group had a cumulative vaccine take after three doses compared with eight (25%) of 32 participants in the placebo group (difference in proportions 0·68, 0·44–0·81; p<0·0001). A serum IgA response was detected in 19 (63%) of 30 participants and 20 (74%) of 27 participants, and stool shedding of RV3-BB was detected in 21 (70%) of 30 participants and 21 (78%) of 27 participants in the neonatal and infant schedule groups, respectively. The frequency of solicited and unsolicited adverse events was similar across the treatment groups. RV3-BB vaccine was not associated with an increased frequency of fever or gastrointestinal symptoms compared with placebo. RV3-BB vaccine was immunogenic and well tolerated when given as a three-dose neonatal or infant schedule. A birth dose strategy of RV3-BB vaccine has the potential to improve the effectiveness and implementation of rotavirus vaccines. Australian National Health and Medical Research Council, the New Zealand Health Research Council, and the Murdoch Childrens Research Institute.

► Transmission of excreted vaccine-derived infectious virus from vaccinated to unvaccinated individuals was assessed. ► Presence of vaccine strain in the stool samples of placebo recipients was an indicator of transmission. ► Immunogenicity and safety of HRV vaccine in transmission cases was assessed. ► Transmission rate was 18.8%; however, they were not associated with increased risk of gastroenteritis. Transmission of excreted vaccine-derived infectious virus from vaccinated to unvaccinated individuals is possible within close contacts. This randomized (1:1), double-blind study evaluated the potential for transmission of human rotavirus vaccine strain, HRV (Rotarix™) from vaccine recipients to unvaccinated close contacts (twins). 100 pairs of healthy twins aged 6–14 weeks at the time of Dose 1 of HRV vaccine/placebo were enrolled and one randomly selected twin from each pair received two vaccine doses and the other received placebo doses (at 2 and 4 months of age). Presence of vaccine strain in the stool samples of placebo recipients was an indicator of transmission. Serial stool samples were tested for rotavirus using ELISA at pre-determined time points; rotavirus positive stool samples were tested with RT-PCR and reverse hybridization assay to identify G1P[8] vaccine strain. If G1P[8] vaccine strain was detected, the complete genome was sequenced to assess the similarity between viral isolates. Immunogenicity and safety of HRV vaccine in transmission cases was assessed. 15 transmission cases were reported in 80 evaluable twins who received placebo and the transmission rate was 18.8% (95% CI: 10.9–29.0%). None of the transmission cases was associated with gastroenteritis symptoms. Anti-rotavirus IgA seroconversion was 62.5% (95% CI: 51.0–73.1%) (HRV) and 21.3% (95% CI: 12.9–31.8%) (placebo) 7-weeks post-Dose 2; seroconversion in transmission cases was 26.7% (95% CI: 7.8–55.1%). Genetic variations or amino acid substitutions in transmission cases were similar to that seen in corresponding vaccine recipients. Transmission of HRV vaccine strain to unvaccinated twins living in close contact occurred, however, they were not associated with increased of gastroenteritis. Whether transmission leads to indirect protection among unvaccinated individuals remains unknown at this stage.

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 .).

Rotavirus vaccines are less effective in high mortality regions. A rotavirus vaccine administered at birth may overcome challenges to vaccine uptake posed by a complex gut microbiome. We investigated the association between the microbiome and vaccine responses following RV3-BB vaccine (G3P[6]) administered in a neonatal schedule (dose 1: 0-5 days), or infant schedule (dose 1: 6-8 weeks) in Indonesia (Phase 2b efficacy study) ( n  = 478 samples/193 infants) (ACTRN12612001282875) and in Malawi (Immunigenicity study) (n = 355 samples/186 infants) (NCT03483116). Vaccine responses assessed using anti-rotavirus IgA seroconversion (IgA), stool shedding of vaccine virus and vaccine take (IgA seroconversion and/or shedding). Here we report, high alpha diversity, beta diversity differences and high abundance of Bacteroides is associated with positive vaccine take and shedding following RV3-BB administered in the neonatal schedule, but not with IgA seroconversion, or in the infant schedule. Higher alpha diversity was associated with shedding after three doses of RV3-BB in the neonatal schedule compared to non-shedders, or the placebo group. High abundance of Streptococcus and Staphylococcus is associated with no shedding in the neonatal schedule group. RV3-BB vaccine administered in a neonatal schedule modulates the early microbiome environment and presents a window of opportunity to optimise protection from rotavirus disease. Here, the authors show that high alpha diversity, differences in beta diversity, and a high abundance of Bacteroides in the gut microbiome are associated with positive vaccine take and stool shedding following administration of RV3-BB vaccine in the neonatal schedule, but not in the infant schedule or placebo groups, suggesting that the early-life gut microbiome provides a gut environment that optimizes the potential for a positive vaccine response.

We conducted a phase I, randomized, double-blind, placebo-controlled trial including healthy adults in Sui County, Henan Province, China. Ninety-six adults were randomly assigned to one of three groups (high-dose, medium-dose, and low-dose) at a 3:1 ratio to receive one vaccine dose or placebo. Adverse events up to 28 days after each dose and serious adverse events up to 6 months after all doses were reported. Geometric mean titers and seroconversion rates were measured for anti-rotavirus neutralizing antibodies using microneutralization tests. The rates of total adverse events in the placebo group, low-dose group, medium-dose group, and high-dose group were 29.17 % (12.62 %–51.09 %), 12.50 % (2.66 %–32.36 %), 50.00 % (29.12 %–70.88 %), and 41.67 % (22.11 %–63.36 %), respectively, with no significant difference in the experimental groups compared with the placebo group. The results of the neutralizing antibody assay showed that in the adult group, the neutralizing antibody geometric mean titer at 28 days after full immunization in the low-dose group was 583.01 (95 % confidence interval [CI]: 447.12–760.20), that in the medium-dose group was 899.34 (95 % CI: 601.73–1344.14), and that in the high-dose group was 1055.24 (95 % CI: 876.28–1270.75). The GMT of serum-specific IgG at 28 days after full immunization in the low-dose group was 3444.26 (95 % CI: 2292.35–5175.02), that in the medium-dose group was 6888.55 (95 % CI: 4426.67–10719.6), and that in the high-dose group was 7511.99 (95 % CI: 3988.27–14149.0). The GMT of serum-specific IgA at 28 days after full immunization in the low-dose group was 2332.14 (95 % CI: 1538.82–3534.45), that in the medium-dose group was 4800.98 (95 % CI: 2986.64–7717.50), and that in the high-dose group was 3204.30 (95 % CI: 2175.66–4719.27). In terms of safety, adverse events were mainly Grades 1 and 2, indicating that the safety of the vaccine is within the acceptable range in the healthy adult population. Considering the GMT and positive transfer rate of neutralizing antibodies for the main immunogenicity endpoints in the experimental groups, it was initially observed that the high-dose group had higher levels of neutralizing antibodies than the medium- and low-dose groups in adults aged 18–49 years. This novel inactivated rotavirus vaccine was generally well-tolerated in adults, and the vaccine was immunogenic in adults (ClinicalTrials.gov number, NCT04626856).

•The RV3-BB rotavirus vaccine is a naturally attenuated, human neonatal rotavirus vaccine.•A Phase I study evaluated the safety of RV3-BB rotavirus vaccine in 60 participants.•One dose of RV3-BB rotavirus vaccine was well tolerated.•Vaccine take was demonstrated in 8/9 infants compared with 2/7 infant placebo recipients.•These data support progression of RV3-BB to Phase II immunogenicity and efficacy trials. RV3 is a human neonatal rotavirus strain (G3P[6]) that has been associated with asymptomatic neonatal infection and replicates well in the infant gut. RV3-BB rotavirus vaccine has been developed as a rotavirus vaccine candidate for administration at birth. A single-centre, double-blind, randomised placebo-controlled Phase I study evaluated the safety and tolerability of a single oral dose of the second generation RV3-BB rotavirus vaccine (8.3×106FFU/mL) in 20 adults, 20 children and 20 infants (10 vaccine and 10 placebo per age cohort). Vaccine take was defined as seroconversion (a 3-fold increase in serum anti-rotavirus IgA or serum neutralising antibody (SNA) from baseline at day 28 post-dose) or evidence of RV3-BB viral replication in the faeces by RT-PCR analysis 3–6 days post-vaccination. RV3-BB presence was confirmed by sequence analysis. The RV3-BB vaccine was well tolerated in all participants, with no pattern of adverse events shown to be associated with the study vaccine. In the infant cohort, vaccine take was demonstrated in 8/9 infants following a single dose of vaccine compared with 2/7 placebo recipients. In the infant vaccine group, 5/9 infants exhibited either IgA or SNA seroconversion and 7/9 infants had evidence of RV3-BB replication on days 3–6, compared with 2/7 infants who seroconverted and 0/10 infants with evidence of replication in the placebo group. Two infants in the placebo group had serological evidence of a rotavirus infection within the 28-day study period: one demonstrated an IgA and the other an SNA response, with wild-type virus replication detected in another infant. A single dose of RV3-BB rotavirus vaccine was well tolerated in adults, children and infants. Most infants (8/9) who received RV3-BB demonstrated vaccine take following a single dose. These data support progression of RV3-BB to Phase II immunogenicity and efficacy trials.

► We combined data from two multicenter randomized double-blind, placebo controlled trials using identical methods in Asia and Africa. ► Combined vaccine efficacy against severe rotavirus gastroenteritis during the first year of life was 58.9% (95% confidence interval=40.0–72.3%). ► Combined vaccine efficacy against all cause severe gastroenteritis was 23% (95% CI=5.4–37.3%). ► The vaccine protected heterotypically, against G serotypes not included within the vaccine formulation. ► Vaccinated children had a reduction in their rate of rotavirus gastroenteritis of any severity when compared to unimmunized children of 3.7 episodes per 100 person-years and for severe rotavirus gastroenteritis of 2.3 episodes per 100 person-years. Efficacy of the pentavalent rotavirus vaccine (PRV), RotaTeq®, against severe rotavirus gastroenteritis (RVGE) was evaluated in two double-blind, placebo-controlled, multicenter Phase III clinical trials conducted in GAVI-eligible countries in Africa (Ghana, Kenya, and Mali) and in Asia (Bangladesh and Vietnam) from March 2007 through March 2009. The findings from each continent have been analyzed and presented separately, according to a single identical protocol. Ad hoc analyses combining data from the five sites were performed to further assess the impact of PRV. 6674 infants (4705 infants from Africa and 1969 infants from Asia), randomized 1:1 to receive 3 doses of PRV/placebo at approximately 6-, 10-, and 14-weeks of age according to each country's EPI schedule, were included in the per protocol efficacy analysis. Breastfeeding and concomitant administration of EPI vaccines, including OPV, were allowed. Episodes of gastroenteritis (GE) in infants who presented to study facilities were captured and scored using the 20-point Vesikari scale. Stool samples were analyzed by rotavirus-specific EIA to detect presence of rotavirus antigen and RT-PCR to determine the G/P genotypes. We assessed efficacy to prevent all-cause GE and RVGE at a variety of cut-off points (score≥11, severe; score≥15, very severe). Vaccine efficacy (VE) against RVGE, regardless of serotype, through the entire follow-up period for any severity, severe (score≥11), and very severe (score≥15) was 33.9%, 95% CI (22.7, 43.5), 42.5%, 95% CI (27.4, 54.6), and 51.2%, 95% CI (26.3, 68.2), respectively. Through the first year of life, VE against severe RVGE was 58.9%, 95% CI (40.0, 72.3) and against all-cause severe GE was 23.0%, 95% CI (5.4, 37.3). VE against severe RVGE caused by non-vaccine G serotypes, G8 and G9, through the entire follow-up period was 87.5%, 95% CI (6.8, 99.7) and 48.0%, 95% CI (−5.5, 75.6), respectively. All G8 strains were associated with P2A[6] (a P-type not contained in PRV), while the majority of the G9 strains were associated with P1A[8] (a P-type contained in PRV). Combining data from the 5 sites strengthens the precision of VE estimates and reveals rising VE with increased RVGE severity. Extrapolating data from VE against severe GE and RVGE suggest that 39% of severe GE episodes during the first year of life were due to rotavirus, highlighting substantial, potentially preventable, public health burden of RVGE. PRV provides protection against non-vaccine serotypes (G8P2A[6]).