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Jiang J.,Centers for Disease Control and Prevention | Jiang B.,Centers for Disease Control and Prevention | Parashar U.,Centers for Disease Control and Prevention | Nguyen T.,The National Institute of Hygiene and Epidemiology | And 2 more authors.

Background:Postlicensure data has identified a causal link between rotavirus vaccines and intussusception in some settings. As rotavirus vaccines are introduced globally, monitoring intussusception will be crucial for ensuring safety of the vaccine programs.Methods:To obtain updated information on background rates and clinical management of intussusception, we reviewed studies of intussusception in children <18 years of age published since 2002. We assessed the incidence of intussusception by month of life among children <1 year of age, seasonality, method of diagnosis, treatment, and case-fatality.Findings:We identified 82 studies from North America, Asia, Europe, Oceania, Africa, Eastern Mediterranean, and Central & South America that reported a total of 44,454 intussusception events. The mean incidence of intussusception was 74 per 100,000 (range: 9-328) among children <1 year of age, with peak incidence among infants 5-7 months of age. No seasonal patterns were observed. A radiographic modality was used to diagnose intussusception in over 95% of the cases in all regions except Africa where clinical findings or surgery were used in 65% of the cases. Surgical rates were substantially higher in Africa (77%) and Central and South America (86%) compared to other regions (13-29%). Case-fatality also was higher in Africa (9%) compared to other regions (<1%). The primary limitation of this review relates to the heterogeneity in intussusception surveillance across different regions.Conclusion:This review of the intussusception literature from the past decade provides pertinent information that should facilitate implementation of intussusception surveillance for monitoring the postlicensure safety of rotavirus vaccines. Source

Trang N.V.,The National Institute of Hygiene and Epidemiology | Yamashiro T.,Nagasaki University | Yamashiro T.,Global Network Initiative | Anh L.T.K.,The National Institute of Hygiene and Epidemiology | And 3 more authors.
Virus Research

Group A rotavirus genotype G1P[8] is the most common strain affecting humans around the world over the past few decades. In this study, we examined genetic variation in the VP7 gene of rotavirus G1P[8] strains, detected in children of four major cities of Vietnam during three different rotavirus seasons: 1998-1999, 2007-2008 and 2008-2009 in order to assess the evolution of the virus over 11 years. Fecal samples (n= 73) from children hospitalized for gastroenteritis caused by G1P[8] rotavirus were analyzed by DNA sequencing of gene 9 encoding the VP7 capsid protein. Phylogenetic analyses indicated that VP7 gene of the G1 strains from 1999 contained a lineage I, while rotaviruses from 2009 clustered in lineage II. Both of these lineages were found co-circulating in 2007-2008 season. While different sublineages of lineage I and II co-circulated in the 1998-1999 and 2007-2008 seasons, almost all strains in 2009 belonged to sub-lineage II-C. In the analysis using selected 10 strains, the VP4 genes of these 2 VP7-G1 lineages were all grouped in F45-like cluster. Deduced amino acid analyses indicated that there were thirteen amino acid substitutions between strains of two lineages. Of those, two were found in antigenic regions A and C, implying possible antigenic differences between these two lineages. The G1P[8] strains in Vietnam are very genetically diverse and dynamic, implying the frequent monitoring on evolution of rotavirus will be important to assess efficacy of rotavirus vaccine in Vietnam. © 2012 Elsevier B.V. Source

Trang N.V.,The National Institute of Hygiene and Epidemiology | Luan L.T.,Center for Research and Production of Vaccines and Biologicals | Kim-Anh L.T.,The National Institute of Hygiene and Epidemiology | Hau V.T.B.,The National Institute of Hygiene and Epidemiology | And 7 more authors.
Journal of Medical Virology

Noroviruses (NoV) and sapoviruses (SaV) are recognized as important causes of acute gastroenteritis in children worldwide. In this study, the prevalence and genetic variability of NoV and SaV were determined in hospitalized children <5 years of age with acute gastroenteritis in Hanoi, Vietnam. A total of 501 fecal specimens collected between November-2007 and October-2008, that previously had been tested for rotavirus (RV), were tested for NoV and SaV by realtime RT-PCR. Positive samples were genotyped by conventional RT-PCR followed by sequencing. GII NoV was detected in 180 (36%) and SaV in 7 (1.4%) of the samples. NoV was detected year-round ranging from 9.5% in April to 81.5% in September among RV negative samples. NoV GII.4 Minerva (2006b) was the dominant genotype (93%) with a few other genotypes detected including GII.3 (4.4%), GII.13 (1.7%), and GII.2 (0.6%) but no GI strains. Only GI and GII SaV strains were detected in this study. No difference in NoV prevalence between age groups was noted. Frequency of vomiting or fever was similar between children with NoV and RV infection, yet, NoV caused diarrhea with longer duration. In conclusion, NoV is the second most frequent cause of diarrhea in hospitalized children in North Vietnam. © 2011 Wiley Periodicals, Inc. Source

Anh D.D.,The National Institute of Hygiene and Epidemiology | Van Trang N.,The National Institute of Hygiene and Epidemiology | Thiem V.D.,The National Institute of Hygiene and Epidemiology | Anh N.T.H.,The National Institute of Hygiene and Epidemiology | And 5 more authors.

We tested a candidate live, oral, rotavirus vaccine (Rotavin-M1™) derived from an attenuated G1P [8] strain (KH0118-2003) isolated from a child in Vietnam. The vaccine was tested first for safety in 29 healthy adults. When deemed safe, it was further tested for safety and immunogenicity in 160 infants (4 groups) aged 6-12 weeks in a dose and schedule ranging study. The vaccine was administered in low titer (106.0FFU/dose) on a 2-dose schedule given 2 months apart (Group 2L) and on a 3-dose schedule given 1 month apart (Group 3L) and in high titer (106.3FFU/dose) in 2 doses 2 months apart (Group 2H) and in 3 doses 1 month apart (Group 3H). For comparison, 40 children (group Rotarix™) were given 2 doses of the lyophilized Rotarix™ vaccine (106.5CCID50/dose) 1 month apart. All infants were followed for 30 days after each dose for clinical adverse events including diarrhea, vomiting, fever, abdominal pain, irritability and intussusception. Immunogenicity was assessed by IgA seroconversion and viral shedding was monitored for 7 days after administration of each dose. Two doses of Rotavin-M1 (106.3FFU/dose) were well tolerated in adults. Among infants (average 8 weeks of age at enrollment), administration of Rotavin-M1 was safe and did not lead to an increased rate of fever, diarrhea, vomiting or irritability compared to Rotarix™, indicating that the candidate vaccine virus had been fully attenuated by serial passages. No elevation of levels of serum transaminase, blood urea, or blood cell counts were observed. The highest rotavirus IgA seroconversion rate (73%, 95%CI (58-88%)) was achieved in group 2H (2 doses - 106.3FFU/dose, 2 months apart). The 2 dose schedules performed slightly better than the 3 dose schedules and the higher titer doses performed slightly better than the lower titer doses. These rates of seroconversion were similar to that of the Rotarix™ group (58%, 95%CI (42-73%)). However more infants who received Rotarix™ (65%) shed virus in their stool after the first dose than those who received Rotavin-M1 (44-48%) (p<0.05) and the percent shedding decreased after subsequent doses of either vaccine. Rotavin-M1 vaccine is safe and immunogenic in Vietnamese infants. A trial in progress will assess the safety, immunogenicity and efficacy of Rotavin-M1 (2 doses at 106.3FFU/dose) in a larger number of infants. The trial registration numbers are NCT01375907 and NCT01377571. © 2011 Elsevier Ltd. Source

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