Population Based Cohort Study for Pediatric Infectious Diseases Research in Vietnam

A population-based cohort study on pediatric infectious diseases was established at Khanh Hoa Province, central Vietnam in 2006, to determine the etiology and risk factors for severe pediatric infectious diseases (SPID) such as acute respiratory infection (ARI), diarrhea and dengue which are the major causes of under 5 mortality. A population census survey was conducted in Nha-Trang and Ninh-Hoa to collect demographic, social-behavioral data and disease burden on SPID. The study site covered a population of 353,525 residing in 75,826 households with 24,781 children less than 5 years. Hospital databases from two hospitals covering the region were obtained. Linking the census and hospital databases, we were able to investigate on a variety of SPID such as environmental tobacco smoking exposure and increased risked of pediatric pneumonia hospitalization, population density, water supply and risk of dengue fever and animal livestock and risk of hospitalized diarrhea. To determine incidence, viral etiology and risk factors for pediatric ARI/pneumonia, we setup a population based prospective hospitalized Pediatric ARI surveillance at Khanh Hoa General Hospital, Nha-Trang in February 2007. The study has revealed RSV, rhinovirus and influenza A as major viral pathogens, role of multiple viral infection and its interaction with bacteria in the development of pneumonia. In addition, we are also conducting a birth cohort study to investigate the incidence of congenital infection and its impact on physical-neurological development, and role of host genetic polymorphism on SPID hospitalization in Vietnam. Population mobility, high cost of regular census update and low mortality are the challenges.

Population based cohort study for Pediatric Infectious Diseases research in Vietnam

A population-based cohort study on pediatric infectious diseases was established at Khanh Hoa Province, central Vietnam in 2006, to determine the etiology and risk factors for severe pediatric infectious diseases (SPID) such as acute respiratory infection (ARI), diarrhea and dengue which are the major causes of under 5 mortality. A population census survey was conducted in Nha-Trang and Ninh-Hoa to collect demographic, social-behavioral data and disease burden on SPID. The study site covered a population of 353,525 residing in 75,826 households with 24,781 children less than 5 years. Hospital databases from two hospitals covering the region were obtained. Linking the census and hospital databases, we were able to investigate on a variety of SPID such as environmental tobacco smoking exposure and increased risked of pediatric pneumonia hospitalization, population density, water supply and risk of dengue fever and animal livestock and risk of hospitalized diarrhea. To determine incidence, viral etiology and risk factors for pediatric ARI/pneumonia, we setup a population based prospective hospitalized Pediatric ARI surveillance at Khanh Hoa General Hospital, Nha-Trang in February 2007. The study has revealed RSV, rhinovirus and influenza A as major viral pathogens, role of multiple viral infection and its interaction with bacteria in the development of pneumonia. In addition, we are also conducting a birth cohort study to investigate the incidence of congenital infection and its impact on physical-neurological development, and role of host genetic polymorphism on SPID hospitalization in Vietnam. Population mobility, high cost of regular census update and low mortality are the challenges.

Antimicrobial susceptibility of Haemophilus influenzae strains isolated from pediatric patients with acute respiratory infection and bacterial meningitis in Hanoi

The molecular characteristics of 44 H. influenzae strains were isolated from children with bacterial meningitis and 37 strains were isolated from children with acute respiratory infection were investigated. Of the 37 H. influenzae isolates from nasopharyngeal aspirates (NA), the serotype of 30 isolates were nontypeable, 4 were type b, 2 were type c and one was type a. Whereas those of 44 isolates from cerebrospinal fluid (CSF) were all type b. Twenty-six (70.3%) from NA and 23 strains from CSF were beta lactamase-producing, and the remaining strains were beta lactamase negative. PCR analysis to identify the resistant genes indicates 25 strains from NA and 21 strains from CSF had TEM-l-type-beta lactamase gene, 11 strains from NA and 22 strains from CSF lack all resistant genes, and each strain from NA and CSF had TEM-l-type beta lactamase gene and fts I gene with the same substitution as the low -betalactamase-negative ampicillin resistant (low-BLNAR) strain. No BLNAR strain was found. The MICs against 16 antibiotics between isolates from NA and CSF were similar except for penicillin G and ampicillin.

Rotavirus diarrhea in Vietnam 1998-2003

Over 5 years we have conducted sentinel surveillance for rotavirus at six hospitals in Vietnam. More than 10,000 children less than 5 years old were admitted with diarrhea with fecal specimens screened for rotavirus. Overall, 55% were positive and there is variability in rates of rotavirus detection between sites (44%-62%). The older age children become infected, the higher percentage of rotavirus detected. the rotavirus strains appear to be the common type.

Acute diarrhea treatment in children under counseling from private pharmacies in Nha Trang, 2004

A randomized investigation was conducted in 30 of total 80 private pharmacies registered enterprise at Nha Trang city from Mar to Apr 2004 to determine real situation of treatment diarrhea for children under advice of the pharmacies. Results: rate of pharmacies advising treatment for diarrhea by ORS are relatively low while ORS drug is used largely and effectively in treatment diarrhea. 87% pharmacies have provided incorrect counseling to their customers.

Drug resistance between M. tuberculosis beijing family and atypical beijing strains in association with BCG vaccination

A study was implemented to determine the frequency of Beijing family and atypical Beijing, two sub-groups of the Mycobacterium tuberculosis Beijing clade detected in Netherlands, Vietnam, and Hong Kong, and to assess the associations between these strains and patient characteristics. The typical Beijing family isolates were more prevalent than atypical Beijing strains and the former isolated from BCG-vaccinated individuals was also more frequently than the latter. The proportion of Beijing family strains was lowest among the patients aged over 75 years. Furthermore, atypical Beijing isolates were resistant to Isoniazide and several drugs, but less often resistant to Streptomycine than the Beijing family isolates

Influence of different dosages of Vi conjugate vaccine (Vi - rEPA) on the immunogenicity in children

In a double blinded study which was conducted at 3 kindergartens of 3 communes of Thanh Ba district and Phu Tho district showed that the effectiveness of Vi-rEPA for typhoid fever in 2-5 year old children reached to 89% for 46 months. Vi-rEPA containing 25mg of Vi induced more than 8 fold rise of IgG anti-Vi in all vaccines. The dosage immunogenicity study of 5, 12.5 and 25mg of Vi-rEPA was injected 6 weeks apart and blood samples were taken before, 10 weeks and 1 year after the first injection. At 10 weeks, the antibody levels of children with 25 mg injections were higher than that of children with 12.5mg and 5mg injection, and all 3 groups had antibody levels declined 7 folds, but still remained significantly higher than before immunization. This study confirmed the safety and immunogenicity of Vi-rEPA

Effectiveness of oral cholera vaccine three to five years after mass vaccination in Hue

From 1998, mass immunization using the locally-produced, killed oral cholera vaccine was conducted in half of the communes of Hue city followed by mass immunization of the remaining communes in 2000. In 2003, a cholera outbreak occurred in the city. The objective of the study is to assess the effects of vaccine after 3-5 years. The control group had the same address, sex and age with cholera patients. From May – August 2003, a total of 115 confirmed cholera cases were detected in Hue city. In this study, 48 cases were positive culture-confirmed and 21 cases was clinically suspected cholera. 62% cases had been vaccinated compared with 75% of the controls. The results showed that, using cholera vaccine in 1998 or 2000 conferred 50% protection against cholera during the 2003 outbreak

A retrospective three-year review of intussusception in Nha Trang, Khanh Hoa province, 2000-2002

The retrospective study reviewed 114 patients under 5 year old, hospitalized for intussusception (IS) over 3 years period (2000-2002) in General Hospital of Khanh Hoa province. The number of cases vary between 29 to 48 annually. Boy to girl ratio was 2:1. 64% of cases were children under 1 year old. The peak of IS was observed between 4 to 9 month old and had no difference in seasonal prevalence. Most common symptoms were abdominal pain, vomiting and abdominal mass. 88% of cases were diagnosed by ultrasound, 12% were confirmed by clinical diagnosis. Majority of cases was cured by radiological reduction. 5 cases must operated after failure of radiological reduction. No fatal case was reported

The infection rate of haemophilus influenzae, streptococcus pneumoniae and respiratory viruses in patients under 5 years old with acute respiratory infection

From Jan. to Oct.2003, the rate of pathological bacteria H. influenzae and S. pneumoniae and viruses adeno, influenzae, entero, isolated from rhino-pharyngeal fluids of 198 pediatric under five years old of age patients with acute inflammation of respiratory tract treated at Hanoi’s St Paul Hospital was determined. The rate of isolated bacteria accounted for 41,9%, viruses 9,1%, and of both 2 bacterial and viral pathological agents in concomittence 4,55% of cases. Among them, isolated S. pneumoniae was the most- 35,8%, following by H.influenzae- 31,2%. 2 bacteria species were isolated in concomittance in 23 case samples. Among isolated viruses, adeno virus occupied 27%, influenzae 16% and entero virus 44%

Bacteremia in children under 5 years of age before using antibiotics

From June 2002 to April 2003, at the Department of Transmissible diseases and the Department of Neonate infants of the Central Hospital of Pediatry and at the Department of Pediatry of Bach Mai Hospital, 189 blood samples of under 5 years old children, who did not use antibiotics within 7 days, underwent a culture. From them, 28 strains of 11 genera of bacteria were isolated. The rate of positive blood culture accounted for 14.8%, in neonate infants 19.6%, there were 71.3% sepsis among under 1 year old children, among them gram(+) bacteria 53.5% were with mainly staphyloccocus, gram(-) bacteria mainly Klebsiella pneumoniae and E.Coli 45.6%. Some bacteria were resistant to common antibiotics such as ampicillin and chloramphenicol