Asia ; epidemiology ; Genotype ; Humans ; Rotavirus ; classification ; genetics ; Rotavirus Infections ; epidemiology ; prevention & control ; virology ; Rotavirus Vaccines ; immunology

Administration, Oral ; Humans ; Rotavirus Infections ; immunology ; prevention & control ; Viral Vaccines ; administration & dosage ; immunology

INTRODUCTIONThis was the first study conducted to evaluate the efficacy of 2 oral doses of the human rotavirus vaccine, RIX4414 in Singaporean infants during the first 3 years of life.

MATERIALS AND METHODSHealthy infants, 11 to 17 weeks of age were enrolled in this randomised (1:1), double-blinded, placebo-controlled study to receive 2 oral doses of RIX4414 vaccine/placebo following a 0-, 1-month schedule. Vaccine efficacy against severe rotavirus (RV) gastroenteritis (Vesikari score ≥11) caused by wild-type RV strains from a period starting from 2 weeks post-Dose 2 until 2 and 3 years of age was calculated with 95% confidence interval (CI). Immunogenicity and safety of the vaccine were also assessed.

RESULTSOf 6542 infants enrolled, 6466 were included in the efficacy analysis and a subset of 100 infants was included in the immunogenicity analysis. Fewer severe RV gastroenteritis episodes were reported in the RIX4414 group when compared to placebo at both 2 and 3 year follow-up periods. Vaccine efficacy against severe RV gastroenteritis at the respective time points were 93.8% (95% CI, 59.9 to 99.9) and 95.2% (95% CI, 70.5 to 99.9). One to 2 months post-Dose 2 of RIX4414, 97.5% (95% CI, 86.8 to 99.9) of infants seroconverted for anti-RV IgA antibodies. The number of serious adverse events recorded from Dose 1 until 3 years of age was similar in both groups.

CONCLUSIONTwo oral doses of RIX4414 vaccine was immunogenic and provided high level of protection against severe RV gastroenteritis in Singaporean children, during the first 3 years of life when the disease burden is highest.

Antibodies, Viral ; immunology ; Double-Blind Method ; Female ; Gastroenteritis ; prevention & control ; virology ; Humans ; Immunogenicity, Vaccine ; Immunoglobulin A ; immunology ; Infant ; Male ; Rotavirus ; immunology ; Rotavirus Infections ; prevention & control ; Rotavirus Vaccines ; immunology ; therapeutic use ; Singapore ; Treatment Outcome ; Vaccines, Attenuated ; immunology ; therapeutic use

OBJECTIVETo evaluate in vivo immunological protective efficacy and safety of expressed recombinant rotavirus epitopes in mice.

METHODSUsing the Flock House virus capsid protein as a vector, three epitopes derived from rotavirus Vp4 amino acid 223-242 [rotavirus epitope A, (REA)], 243-262 [rotavirus epitope B, (REB)], and 234-251 [rotavirus epitope C, (REC)] were genetically engineered on the surface of the vector protein and expressed in pET-3 (E. coli BL21 [DE3]) system into multiple epitopes, REABC, which comprises REA, REB, and REC. Kunming strain mice were inoculated with the recombinant epitopes REABC, and then challenged perorally by cell culture-adapted rotavirus Wa (type G1P1A) and SA11 (type G3P2). Infection syndrome was observed, and virus antigen in stools of mice and serum neutralizing antibody activities were determined and analyzed.

RESULTSThe recombinant epitopes REABC significantly induced rotavirus specific neutralyzing antibodies against WA and SA11, reduced virus reproduction, elicitted immune memory in inoculated mice, and protected inoculated mice from challenge by WA or SA11 (P<0.001).

CONCLUSIONThe recombinant epitopes have high immunological protective efficacy and mild side effects in mice. It may be used as an epitope-based vaccine candidate in human.

Animals ; Antigens, Viral ; immunology ; Capsid ; immunology ; metabolism ; Capsid Proteins ; immunology ; Epitopes ; biosynthesis ; immunology ; Escherichia coli ; genetics ; Female ; Genetic Vectors ; Male ; Mice ; Random Allocation ; Recombinant Proteins ; biosynthesis ; immunology ; Rotavirus ; immunology ; Rotavirus Infections ; immunology ; prevention & control ; Viral Vaccines ; immunology

OBJECTIVETo observe the serum immune responses and protection in mice model of the recombinant adenovirus vector mediated human rotavirus VP6 gene expression through coden optimization (rvAdVP6(o)) in comparison with the wild type (rvAdVP6).

METHODS6-8 week female BALB/c mice were randomly grouped and immunized three times intranasally with 10(8) TCID50 rvAdVP6(o) and rvAdVP6, respectively, then detect the serum IgG level against rotavirus induced by rvAdVP6(o) and rvAdVP6. The amount of sheding viral antigens in feces was detectd after mice rotavirus was taked orally.

RESULTSThe serum IgG level against rotavirus induced by rvAdVP6(o) was higher than that of rvAdVP6 after three times of immunization. The immunized mice shed lower amount of viral antigens in feces as compared with the rvAdVP6.

CONCLUSIONThe recombinant adenovirus which encode optimized human rotavirus VP6 proteins (rvAdVP6(o)) could induce stronger serum immune and protective responses against the challenge of the rotavirus than the wild type (rvAdVP6) at the same immunizing dosage.

Animals ; Antibodies, Viral ; blood ; Antigens, Viral ; genetics ; immunology ; Capsid Proteins ; genetics ; immunology ; Codon ; genetics ; Disease Models, Animal ; Female ; Humans ; Immunization ; Immunoglobulin G ; blood ; Mice ; Mice, Inbred BALB C ; Rotavirus Infections ; prevention & control ; Rotavirus Vaccines ; immunology ; Vaccines, Synthetic ; immunology

INTRODUCTIONThe world's first rotavirus vaccine, Rotashield or RRV-TV, was registered in the US in 1998, but withdrawn within a year because of an observed association with intussusception (IS). Surveillance for IS has consequently become important in safety monitoring of new-generation rotavirus vaccines during development. Post-marketing surveillance is also important, and requires the availability of local baseline epidemiology data on IS.

MATERIALS AND METHODSAn eight-year study of IS in children under 2 years of age in Singapore was performed by retrospective review of admissions to KK Women's and Children's Hospital, the main paediatric hospital, from 1997 to 2001, followed by prospective surveillance of all hospitals from 2001 to 2004, using the case definition of the Brighton Collaboration Intussusception Working Group.

RESULTSThe average IS incidence was 60 per 100,000 in under-ones, and 32 per 100,000 in under-twos, with a downward trend between 1999 and 2004. Ninety-two per cent of subjects were aged below one year, with 51% aged 6 months to 11 months. The mean age at which IS occurred increased from 6.4 months to 12.5 months over the study period. The male-to-female ratio was 1.3:1. No trend in IS numbers was observed over different months of the year.

CONCLUSIONIS in Singapore shows no seasonality, but has demonstrated a trend of decreasing incidence in recent years. While highest in the first year of life, the risk of IS is increasing in the second year of life. Males have a slightly higher risk.

Child, Preschool ; Female ; Humans ; Immunization Programs ; Incidence ; Infant ; Infant, Newborn ; Intussusception ; chemically induced ; epidemiology ; Male ; Prospective Studies ; Retrospective Studies ; Risk Assessment ; Risk Factors ; Rotavirus ; immunology ; Rotavirus Infections ; prevention & control ; Rotavirus Vaccines ; adverse effects ; Singapore ; epidemiology ; Vaccination ; adverse effects

Rotavirus (RV) is one of the most important viral etiologic agents of acute gastroenteritis (AGE) in children. Although effective RV vaccines (RVVs) are now used worldwide, novel genotypes and outbreaks resulting from rare genotype combinations have emerged. This study documented RV genotypes in a Korean population of children with AGE 5 yr after the introduction of RVV and assessed potential genotype differences based on vaccination status or vaccine type. Children less than 5-yr-old diagnosed with AGE between October 2012 and September 2013 admitted to 9 medical institutions from 8 provinces in Korea were prospectively enrolled. Stool samples were tested for RV by enzyme immunoassay and genotyped by multiplex reverse-transcription polymerase chain reaction. In 346 patients, 114 (32.9%) were RV-positive. Among them, 87 (76.3%) patients were infected with RV alone. Eighty-six of 114 RV-positive stool samples were successfully genotyped, and their combinations of genotypes were G1P[8] (36, 41.9%), G2P[4] (12, 14.0%), and G3P[8] (6, 7.0%). RV was detected in 27.8% of patients in the vaccinated group and 39.8% in the unvaccinated group (P=0.035). Vaccination history was available for 67 of 86 cases with successfully genotyped RV-positive stool samples; RotaTeq (20, 29.9%), Rotarix (7, 10.4%), unvaccinated (40, 59.7%). The incidence of RV AGE is lower in the RV-vaccinated group compared to the unvaccinated group with no evidence of substitution with unusual genotype combinations.
Child, Preschool ; Feces/virology ; Gastroenteritis/immunology/prevention & control/virology ; Genotype ; Humans ; Infant ; *Mass Vaccination ; RNA, Viral/genetics ; Republic of Korea ; Reverse Transcriptase Polymerase Chain Reaction ; Rotavirus/*classification/*genetics/isolation & purification ; Rotavirus Infections/immunology/*prevention & control/virology ; Rotavirus Vaccines/*immunology ; Vaccines, Attenuated/immunology

INTRODUCTIONIn recent years, acellular pertussis combination vaccines have facilitated compliance with and coverage of the national immunisation programme in Singapore. This phase-II study (Rota-007) evaluated the immunogenicity, reactogenicity and safety of a DTPa-IPV/Hib combined vaccine when co-administered with a rotavirus vaccine.

MATERIALS AND METHODSA total of 2464 children aged 3 months were vaccinated with DTPa-IPV/Hib together with a randomised 1:3 ratio of either placebo (n=653) or 1 of 3 different formulations of a rotavirus vaccine. Blood samples were collected for immunogenicity analysis 1 month after the third DTPa-IPV/Hib vaccine dose in a subset of subjects (n = 640). Local and general reactogenicity and unsolicited adverse events were recorded during the follow-up after each vaccination.

RESULTSSerological analysis showed >95% response for all antigens in the co-administered DTPa-IPV/Hib vaccine, with no difference between the rotavirus vaccine and placebo groups. No differences in adverse events and reactogenicity were reported in the rotavirus vaccine and placebo groups. Only 0.2% of the subjects reported Grade 3 adverse events. Three subjects (from the vaccine groups) died during the study, which were assessed by the investigators as unrelated to vaccination. No deaths were reported in the placebo group.

CONCLUSIONThe combined DTPa- IPV/Hib vaccine is safe, well tolerated and highly immunogenic when given alone or coadministered with the rotavirus vaccine for infants in Singapore.

Child ; Child Welfare ; Child, Preschool ; Double-Blind Method ; Female ; Haemophilus Infections ; immunology ; prevention & control ; Haemophilus influenzae type b ; isolation & purification ; Humans ; Infant ; Infant, Newborn ; Male ; Patient Compliance ; Poliomyelitis ; prevention & control ; Rotavirus Vaccines ; Singapore ; Vaccines, Combined ; Vaccines, Conjugate ; adverse effects ; immunology