Paul Gillard

Effect of Human Rotavirus Vaccine on Severe Diarrhea in African Infants

BACKGROUND Rotavirus is the most common cause of severe gastroenteritis among young children worldwide. Data are needed to assess the efficacy of the rotavirus vaccine in African children. METHODS We conducted a randomized, placebo-controlled, multicenter trial in South Africa (3166 infants; 64.1% of the total) and Malawi (1773 infants; 35.9% of the total) to evaluate the efficacy of a live, oral rotavirus vaccine in preventing severe rotavirus gastroenteritis. Healthy infants were randomly assigned in a 1:1:1 ratio to receive two doses of vaccine (in addition to one dose of placebo) or three doses of vaccine--the pooled vaccine group--or three doses of placebo at 6, 10, and 14 weeks of age. Episodes of gastroenteritis caused by wild-type rotavirus during the first year of life were assessed through active follow-up surveillance and were graded with the use of the Vesikari scale. RESULTS A total of 4939 infants were enrolled and randomly assigned to one of the three groups; 1647 infants received two doses of the vaccine, 1651 infants received three doses of the vaccine, and 1641 received placebo. Of the 4417 infants included in the per-protocol efficacy analysis, severe rotavirus gastroenteritis occurred in 4.9% of the infants in the placebo group and in 1.9% of those in the pooled vaccine group (vaccine efficacy, 61.2%; 95% confidence interval, 44.0 to 73.2). Vaccine efficacy was lower in Malawi than in South Africa (49.4% vs. 76.9%); however, the number of episodes of severe rotavirus gastroenteritis that were prevented was greater in Malawi than in South Africa (6.7 vs. 4.2 cases prevented per 100 infants vaccinated per year). Efficacy against all-cause severe gastroenteritis was 30.2%. At least one serious adverse event was reported in 9.7% of the infants in the pooled vaccine group and in 11.5% of the infants in the placebo group. CONCLUSIONS Human rotavirus vaccine significantly reduced the incidence of severe rotavirus gastroenteritis among African infants during the first year of life. (ClinicalTrials.gov number, NCT00241644.)

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

Zambia has a population of approximately 12 million. According to estimates from the 2001-2002 Zambia Demographic and Health Survey1 between 1997 and 2001 the rate of neonatal mortality was 37/1000 births the infant mortality rate was 95/1000 births and the maternal mortality ratio was 729/100 000 live births. In order to protect mothers and their newborn babies against tetanus WHO recommends that tetanus toxoid (TT) vaccine be given to all pregnant women; Zambia follows WHOs recommendations. In 2006 79% of all pregnant women received a protective dose of TT vaccine. A total of 60% of all deliveries took place in hygienic conditions (administrative data). WHO and UNICEF estimate that in 2006 90% of births were protected against tetanus. (excerpt)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.

Immunogenicity and safety in adults of one dose of influenza A H1N1v 2009 vaccine formulated with and without AS03A-adjuvant: Preliminary report of an observer-blind, randomised trial

Governments and public health officials are preparing vaccination campaigns against the 2009 influenza A H1N1v pandemic strain. We evaluated two inactivated split-virion A/California/7/2009 H1N1v pandemic vaccines formulated with/without AS03(A), an oil-in-water emulsion adjuvant system containing tocopherol. This ongoing observer-blind study randomised 130 healthy adults aged 18-60 years to receive either AS03(A)-adjuvanted H1N1 vaccine containing 5.25 microg haemagglutinin (HA) (N=64) or non-adjuvanted H1N1 vaccine containing 21 microg HA (N=66) on Days 0 and 21. We performed a first analysis of reactogenicity and serum haemagglutination-inhibition (HI) antibody responses, 21 days after dose 1. Before vaccination, 12.5% in the AS03(A)-adjuvanted group and 13.1% in the non-adjuvanted group had vaccine-homologous HI titres >or=1:40. Immune responses were robust; HI seroconversion rates were 98.2% and 95.1% and HI seroprotection rates were 98.2% and 98.4%, respectively in the AS03(A) and non-adjuvanted groups. The vaccines were well tolerated with similar adverse event profiles. Solicited injection site and general symptoms were reported more frequently for AS03(A)-adjuvanted vaccine but these were transient and mainly mild to moderate in intensity. Based on accepted immunological surrogates, these preliminary data suggest that one dose of either AS03(A)-adjuvanted H1N1v vaccine at a reduced HA dose or non-adjuvanted H1N1v vaccine at a fourfold higher dose is sufficient to immunise healthy adults. The strong immune response is consistent with prevalent immunological priming but as this and the ability to mount immune response after vaccination may be modulated by age, further investigations in children and in the elderly as well as on the persistence of the immune response are warranted.

Priming with AS03A-adjuvanted H5N1 influenza vaccine improves the kinetics, magnitude and durability of the immune response after a heterologous booster vaccination: An open non-randomised extension of a double-blind randomised primary study

An influenza vaccine with cross-immunogenic potential could play a key role in pandemic mitigation by promoting a rapid immune response to infection and/or subsequent vaccination with strains drifted from the primary vaccine strain. Here we assess the role of AS03(A) (an oil-in-water emulsion based Adjuvant System containing tocopherol) in this prime-boost concept using H5N1 as a model shift influenza antigen. In this open, non-randomised study (NCT00506350; an extension of an earlier randomised study) we assessed immunogenicity in nine groups of 35-50 volunteers aged 19-61 years following administration of AS03(A)-adjuvanted split-virion H5N1 vaccine containing 3.75mug of haemagglutinin (HA) from the A/Indonesia/5/2005(IBCDC-RG2) clade 2.1 strain. A single booster dose of vaccine was administered to four groups primed 14 months previously with different HA levels of AS03(A)-adjuvanted clade 1 A/Vietnam/1194/2004 H5N1 vaccine. Two booster doses (given 21 days apart) were administered to four groups primed 14 months previously with different HA levels of non-adjuvanted A/Vietnam/1194/2004 H5N1 vaccine and also to a control group of un-primed subjects. In individuals primed 14 months earlier with AS03(A)-adjuvanted A/Vietnam/1194/2004 vaccines, a single booster dose of AS03(A)-adjuvanted A/Indonesia/5/2005 induced rapid immune responses (licensure criteria met in 7-14 days) comparable to that observed in the un-primed control group following two doses of adjuvanted vaccine. In contrast, individuals primed with non-adjuvanted formulations exhibited minimal immune responses which, even after two doses, were unexpectedly much lower than that observed in un-primed subjects. AS03(A) enhances the initial priming effect of pandemic influenza vaccination enabling a rapid humoral response to single dose boosting with a heterologous strain at 14 months. In contrast, priming without adjuvant appears to inhibit the response to subsequent vaccination with a heterologous strain. These findings should guide the development of vaccines to combat the present influenza A/H1N1 pandemic.

Immunogenicity and safety of AS03-adjuvanted 2009 influenza A H1N1 vaccine in children 6-35 months.

We report on the evaluation of the immunogenicity and reactogenicity/safety of AS03-adjuvanted vaccine against pandemic influenza A/H1N1/2009 in young children. In this open-label, randomized study, 157 healthy children aged 6-35 months received two doses (21 days apart) of split-virion inactivated A/California/7/2009 H1N1 vaccine containing either (i) 1.9microg hemagglutinin (HA) and AS03(B) (5.93mg tocopherol) (N=104) or (ii) 3.75mug HA and AS03(A) (11.86mg tocopherol) (N=53). At 21 days following the first dose of AS03(B)-adjuvanted vaccine (1.9microg HA) the percentage of children with hemagglutination-inhibition titers of >or=40 against the vaccine strain rose from 3.0% before vaccination to 100%. The seroconversion rate was 99% and the geometric mean titer (GMT) increased from 6 to 313. After the second dose the GMT increased further to 2008. The higher dose AS03(A)-adjuvanted 3.75microg HA vaccine did not further increase the immune response. Solicited symptoms reported within 7 days following vaccination were mainly mild to moderate. After the first dose of AS03(B)-adjuvanted vaccine (1.9microg HA) the most common solicited symptoms were pain at the injection site (35.6%) and irritability (31.7%). Fever (axillary >or=37.5 degrees C) was reported with an incidence of 20.2%. After the second dose reactogenicity tended to increase (injection site pain: 41.3%; irritability: 46.2%; fever >or=37.5 degrees C: 67.3%). Spontaneously reported adverse events with an intensity that prevented normal activities were documented for 2.9-6.7% of doses with only one event (vomiting) considered related to vaccination. There was one serious adverse event reported in the AS03(A)-adjuvanted 3.75microg HA vaccine group (traumatic brain injury) which was not considered as related to vaccination. In conclusion, these data suggest that a first dose of AS03(B)-adjuvanted A/H1N1/2009 vaccine containing 1.9microg HA in children 6-35 months old is highly immunogenic and that the overall reactogenicity profile is acceptable although reactions including fever tend to increase after a second dose.

Immunogenicity and tolerability of an AS03A-adjuvanted prepandemic influenza vaccine: A phase III study in a large population of Asian adults

The immunogenicity and lot-to-lot consistency of an AS03-adjuvanted H5N1 vaccine were evaluated in 1206 Asian adults, randomised to receive two doses of adjuvanted (3.75 microg haemagglutinin) or diluent-mixed vaccines, 21 days apart. Post-Dose 2, 96.0% of vaccinees in the H5N1-AS03 group demonstrated a four-fold increase in neutralising antibody titres against the vaccine strain A/Vietnam/1194/2004 and 91.4% against strain A/Indonesia/05/2005. Haemagglutination-inhibiting antibodies (titre > or = 1:40) against A/Vietnam/1194/2004 and A/Indonesia/05/2005 strains were observed in 94.3% and 50.2% of subjects, respectively. Lot-to-lot consistency of the AS03-adjuvanted vaccine combinations was demonstrated. The AS03-adjuvanted vaccine was well tolerated, induced a high frequency of immune responses to the vaccine strain, allowed antigen sparing and promoted cross-clade immunity. These characteristics make it suitable for presumptive use if an H5N1 pandemic were considered to be imminent.

Immunogenicity and Safety of H5N1 A/Vietnam/1194/2004 (Clade 1) AS03-adjuvanted prepandemic candidate influenza vaccines in children aged 3 to 9 years: a phase ii, randomized, open, controlled study.

Background: The development of vaccines against pandemic influenza viruses for use in children is a public health priority. Methods: In this phase II, randomized, open study, the immunogenicity and reactogenicity of H5N1 A/Vietnam/1194/2004 (NIBRG-14) (clade 1) prepandemic influenza vaccine were assessed in children aged 3 to 5 and 6 to 9 years. Children were randomized to receive 2 doses, given 21 days apart, of A/Vietnam/1194/2004 vaccine containing 1.9 &mgr;g or 3.75 &mgr;g hemagglutinin antigen (HA), adjuvanted with a tocopherol-based oil-in-water emulsion (AS03) containing 11.86 mg (AS03A) or 5.93 mg (AS03B) tocopherol. Control groups received 2 doses of trivalent influenza vaccine (TIV). Humoral immune responses, reactogenicity, and safety were the primary outcome measures; cross-reactivity and cell-mediated responses were also assessed (NCT00502593). Results: Between 49 and 51 children in each age stratum (aged 3–5 and 6–9 years) received H5N1 vaccine, and between 17 and 18 children in each age stratum received TIV. After the second dose, recipients of H5N1 vaccine (1.9 &mgr;g HA/AS03B, 3.75 &mgr;g HA/AS03B, and 3.75 &mgr;g HA/AS03A) achieved humoral antibody titers against the vaccine-homologous strain, which fulfilled the United States influenza vaccines licensure criteria for immunogenicity. With the exception of 1 child, there were no H5N1 immune responses in children who received TIV. The most frequent injection-site event was pain in all groups, and the H5N1 vaccine had a clinically acceptable reactogenicity and safety profile. Exploratory analyses in children aged 3 to 5 years indicated that the induction of CD4+ T-cell responses polarized in favor of a T-helper 1 profile. Conclusions: The results showed that 2 doses of AS03-adjuvanted H5N1 influenza vaccine at antigen-sparing doses of 1.9 &mgr;g or 3.75 &mgr;g HA elicited broad and persistent immune responses with acceptable reactogenicity, and without safety concerns, in children aged 3 to 9 years.

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].

Horizontal transmission of a human rotavirus vaccine strain--a randomized, placebo-controlled study in twins.

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 vaccine manufacturer’s approach to address medical needs related to seasonal and pandemic influenza viruses

Abstract Vaccination is considered to be one of the most effective tools to decrease morbidity as well as mortality caused by influenza viruses.