Treatment costs of pneumonia, meningitis, sepsis, and other diseases among hospitalized children in Viet Nam

The aim of this study was to estimate the costs of treatment of children who present with the signs and symptoms of invasive bacterial diseases in Khanh Hoa province, Viet Nam. The study was an incidence-based cost-of-illness analysis from the health system perspective. The hospital costs included labour, materials and capital costs, both direct and indirect. Costs were determined for 980 children, with an average age of 12.67 months (standard deviation +/- 11.38), who were enrolled in a prospective surveillance at the Khanh Hoa General Hospital during 2005-2006. Of them, 57% were male. By disease-category, 80% were suspected of having pneumonia, 8% meningitis, 3% very severe disease consistent with pneumococcal sepsis, and 9% other diseases. Treatment costs for suspected pneumonia, meningitis, very severe disease, and other diseases were US$ 31, US$ 57, US$ 73, and US$ 24 respectively. Costs ranged from US$ 24 to US$ 164 across different case-categories. Both type of disease and age of patient had statistically significant effects on treatment costs. The results showed that treatment costs for bacterial diseases in children were considerable and might differ by as much as seven times among invasive pneumococcal diseases. Changes in costs were sensitive to both age of patient and case-category. These cost-of-illness data will be an important component in the overall evidence base to guide the development of vaccine policy in Viet Nam.

Can daytime use of bed nets not treated with insecticide reduce the risk of dengue hemorrhagic fever among children in Vietnam?

The purpose of this study was to investigate the prevalence of bed net use and elucidate the effect of daytime bed net use on preventing dengue hemorrhagic fever (DHF) among children in Vietnam. We conducted a population-based cross-sectional survey and a matched case-control study in Khanh Hoa Province where not only some pre-schoolchildren but also some school children, who take a nap during lunch break prior to returning to school, used bed nets during the day. Among 36,901 children 2-10 years of age, most used untreated bed nets during the night (98.3%) compared with 8.4% during the day. The results of the case-control study, which defined 151 cases who were hospitalized with DHF in the provincial hospitals and 604 age-matched neighborhood controls, did not support our hypothesis that children using untreated bed nets during the day are less likely to be hospitalized with DHF (adjusted odds ratio = 0.56, 95% confidence interval = 0.23-1.39).

Surveillance of pneumococcal-associated disease among hospitalized children in Khanh Hoa Province, Vietnam

BACKGROUND

To understand the epidemiology of childhood bacterial diseases, including invasive pneumococcal disease, prospective surveillance was conducted among hospitalized children in Nha Trang, Vietnam.

METHODS

From April 2005 through August 2006, pediatricians at the Khanh Hoa General Hospital used standardized screening criteria to identify children aged <5 years who had signs and symptoms of invasive bacterial disease. All cerebrospinal fluid (CSF) and blood specimens collected were tested by bacterial culture. Selected culture-negative specimens were tested for Streptococcus pneumoniae by antigen detection or for Haemophilus influenzae, Moraxella catarrhalis, Neisseria meningitidis, and S. pneumoniae by polymerase chain reaction (PCR).

RESULTS

A total of 987 children were enrolled (794 with pneumonia, 76 with meningitis, and 117 with other syndromes consistent with invasive bacterial disease); 84% of children were aged 0-23 months, and 57% were male. Seven (0.71%) of 987 blood cultures and 4 (15%) of 26 CSF cultures were positive for any bacterial pathogen (including 6 for H. influenzae type b and 1 for S. pneumoniae). Pneumococcal antigen testing and PCR identified an additional 16 children with invasive pneumococcal disease (12 by antigen testing and 4 by PCR). Among children aged <5 years who lived in Nha Trang, the incidence rate of invasive pneumococcal disease was at least 48.7 cases per 100,000 children (95% confidence interval, 27.9-85.1 cases per 100,000 children).

CONCLUSIONS

S. pneumoniae and H. influenzae type b were the most common causes of laboratory-confirmed invasive bacterial disease in children. PCR and antigen testing increased the sensitivity of detection and provided a more accurate estimate of the burden of invasive bacterial disease in Vietnam.

Association of environmental tobacco smoking exposure with an increased risk of hospital admissions for pneumonia in children under 5 years of age in Vietnam

BACKGROUND

The association between environmental tobacco smoking (ETS) and childhood pneumonia has not been established in developed or developing countries. A study was conducted to assess the effect and impact of ETS exposure on pneumonia among children in central Vietnam.

METHODS

A population-based large-scale cross-sectional survey was conducted covering all residents of 33 communes in Khanh Hoa Province, the central part of Vietnam. Information on demographics, socioeconomic status and house environment, including smoking status of each household member, was collected from householders. Hospital admissions for pneumonia among children aged <5 years in each household in the previous 12 months were recorded based on caregiver's report.

RESULTS

A total of 353 525 individuals living in 75 828 households were identified in the study areas. Of these, 24 781 (7.0%) were aged <5 years. The prevalence of ETS was 70.5% and the period prevalence of hospital admissions for pneumonia was 2.6%. Multiple logistic regression analysis showed that exposure to ETS was independently associated with hospital admissions for pneumonia (adjusted odds ratio 1.55, 95% CI 1.25 to 1.92). The prevalence of tobacco smoking was higher among men than women (51.5% vs 1.5%). It is estimated that 28.7% of childhood pneumonia in this community is attributable to ETS.

CONCLUSIONS

Children in Vietnam are exposed to substantial levels of ETS which results in 44 000 excess hospital admissions due to pneumonia each year among children aged <5 years.

Drug-resistant pneumococci in children with acute lower respiratory infections in Vietnam

BACKGROUND

Acute lower respiratory infections (ALRI), primarily pneumonia, are the leading cause of death in children under 5 years of age. Most of these deaths occur in Africa and southeast Asia. Increasing rates of drug resistance in pneumococcal strains emphasize the necessity of prevention of pneumococcal vaccines. The aim of the present study was to determine the frequency of drug resistance and the distribution of serotype of pneumococcal strains isolated from pediatric patients with ALRI in Vietnam.

METHODS

Two hundred and twenty pediatric patients with ALRI under 5 years of age were enrolled in Hanoi, Vietnam between 2001 and 2002. Bacterial pathogens with a heavy growth (10(6) c.f.u./mL) were isolated from nasopharyngeal secretions on quantitative culture. Fifty-three pneumococcal strains isolated from the nasopharynx of pediatric patients were examined for antibiotic susceptibility including drug-resistant genes and serotyping.

RESULTS

A total of 73.6% of pneumococcal strains were genotypic penicillin-resistant Streptococcus pnemoniae (gPRSP), possessing altered penicillin-binding protein genes pbp 1a + 2x + 2b; 67.9% of these strains were gPRSP and simultaneously had the ermB gene, which is responsible for high resistance to erythromycin. The majority of gPRSP strains were serotype 19F or 23F.

CONCLUSION

gPRSP strains with serotype 19F or 23F are highly prevalent among pediatric patients with ALRI under 5 years of age in Hanoi, Vietnam.

Survey of childhood empyema in Asia: implications for detecting the unmeasured burden of culture-negative bacterial disease

Background

Parapneumonic empyema continues to be a disease of significant morbidity and mortality among children despite recent advances in medical management. To date, only a limited number of studies have assessed the burden of empyema in Asia.

Methods

We surveyed medical records of four representative large pediatric hospitals in China, Korea, Taiwan and Vietnam using ICD-10 diagnostic codes to identify children <16 years of age hospitalized with empyema or pleural effusion from 1995 to 2005. We also accessed microbiology records of cultured empyema and pleural effusion specimens to describe the trends in the epidemiology and microbiology of empyema.

Results

During the study period, we identified 1,379 children diagnosed with empyema or pleural effusion (China, n = 461; Korea, n = 134; Taiwan, n = 119; Vietnam, n = 665). Diagnoses of pleural effusion (n = 1,074) were 3.5 times more common than of empyema (n = 305), although the relative proportions of empyema and pleural effusion noted in hospital records varied widely between the four sites, most likely because of marked differences in coding practices. Although pleural effusions were reported more often than empyema, children with empyema were more likely to have a cultured pathogen. In addition, we found that median age and gender distribution of children with these conditions were similar across the four countries. Among 1,379 empyema and pleural effusion specimens, 401 (29%) were culture positive. Staphylococcus aureus (n = 126) was the most common organism isolated, followed by Streptococcus pneumoniae (n = 83), Pseudomonas aeruginosa (n = 37) and Klebsiella (n = 35) and Acinetobacter species (n = 34).

Conclusion

The age and gender distribution of empyema and pleural effusion in children in these countries are similar to the US and Western Europe. S. pneumoniae was the second leading bacterial cause of empyema and pleural effusion among Asian children. The high proportion of culture-negative specimens among patients with pleural effusion or empyema suggests that culture may not be a sufficiently sensitive diagnostic method to determine etiology in the majority of cases. Future prospective studies in different countries would benefit from standardized case definitions and coding practices for empyema. In addition, more sensitive diagnostic methods would improve detection of pathogens and could result in better prevention, treatment and outcomes of this severe disease.

Reliability and validity of the Vietnamese version of the Pregnancy Physical Activity Questionnaire (PPAQ)

This study aimed to translate the Pregnancy Physical Activity Questionnaire (PPAQ) into Vietnamese, and test its reliability and validity among Vietnamese pregnant women. Intraclass correlation (ICC) and the Bland and Altman method were used to assess the test-retest reliability of the PPAQ. The Pearson correlations coefficient between the PPAQ measurements and those obtained from a pedometer that measured step counts (10-day averages) were used to determine the validity of the questionnaire. The PPAQ was successfully translated from English into Vietnamese with face validity through a rigorous process of the cross-cultural validation. For the analysis of reliability, the ICC value was 0.88 (95% CI 0.83-0.94) for total activity, 0.94 for sedentary, 0.88 for light, 0.90 for moderate, and 0.87 for vigorous activities. The Bland and Altman analysis showed that the first and second PPAQ total scores did not significantly differ from zero, and mostly fell within the range of 0 +/- 1.96 SD. The analysis of validity showed that there were moderate correlations with statistically significance (p = 0.02) between the step counts and PPAQ total. Our study indicates that the Vietnamese PPAQ is within acceptable reliability and validity.

Temporal trends and climatic factors associated with bacterial enteric diseases in Vietnam, 1991-2001

OBJECTIVE

In Vietnam, shigellosis/dysentery, typhoid fever, and cholera are important enteric diseases. To better understand their epidemiology, we determined temporal trends, seasonal patterns, and climatic factors associated with high risk periods in eight regions across Vietnam.

METHODS

We quantified monthly cases and incidence rates (IR) for each region from national surveillance data (1991-2001). High- and low-disease periods were defined from the highest and lowest IRs (1 SD above and below the mean) and from outbreaks from positive outliers (4 SDs higher in 1 month or 2 SDs higher in > or = 2 consecutive months). We used general linear models to compare precipitation, temperature, and humidity between high- and low-risk periods.

RESULTS

Shigellosis/dysentery was widespread and increased 2.5 times during the study period, with the highest average IRs found between June and August (2.1/100,000-26.2/100,000). Typhoid fever was endemic in the Mekong River Delta and emerged in the Northwest in the mid-1990s, with peaks between April and August (0.38-8.6). Cholera was mostly epidemic along the central coast between May and November (0.07-2.7), and then decreased dramatically nationwide from 1997 onward. Significant climate differences were found only between high- and low-disease periods. We were able to define 4 shigellosis/dysentery, 14 typhoid fever, and 8 cholera outbreaks, with minimal geotemporal overlap and no significant climatic associations.

CONCLUSIONS

In Vietnam, bacterial enteric diseases have distinct temporal trends and seasonal patterns. Climate plays a role in defining high- and low-disease periods, but it does not appear to be an important factor influencing outbreaks.

Rotavirus G5P[6] in child with diarrhea, Vietnam

We detected rotavirus G5P[6] with a long RNA pattern in a Vietnamese child with diarrhea. Viral outer capsid protein VP7 and VP4 genes suggest that it likely originated from porcine rotavirus either by genetic reassortment or as whole virions. To our knowledge, this is the first report of human rotavirus G5 in Asia.

Increased rates of intense nasopharyngeal bacterial colonization of Vietnamese children with radiological pneumonia

Acute lower respiratory infection (ALRI), primarily pneumonia, is the leading cause of death in children under the age of five. Bacterial ALRI is preceded by asymptomatic bacterial colonization. Bacterial colonization, therefore, may have an important role in the development of pneumonia in children. This case-control study was conducted in order to determine if intense bacterial colonization was increased in the nasopharynx of pediatric patients with ALRI. One hundred-sixty four pediatric patients with ALRI and 70 healthy children < 5 years of age were enrolled in Hanoi, Vietnam between 2001 and 2002. Bacterial pathogens were isolated from nasopharyngeal secretions and quantitatively cultured. Of 164 patients, 91 were diagnosed as having radiological pneumonia (PN group) and 73 as having acute bronchitis (AB group). Intense growth of any bacterial pathogen (>or= 10(6) colony-forming units/ml) was highest in the PN group (49.4%), followed by the AB group (28.8%), with healthy children having the lowest (17.1%). Patients with intense bacterial growth were more likely to develop pneumonia, but not acute bronchitis, than were patients with light or no bacterial growth. The results of this case-control study suggest that the vertical spread of intense bacterial pathogens colonized in the nasopharynx to the lower airway leads to bacterial pneumonia in children under the age of five.

Antimicrobial drug resistance of Salmonella enterica serovar typhi in asia and molecular mechanism of reduced susceptibility to the fluoroquinolones

This study describes the pattern and extent of drug resistance in 1,774 strains of Salmonella enterica serovar Typhi isolated across Asia between 1993 and 2005 and characterizes the molecular mechanisms underlying the reduced susceptibilities to fluoroquinolones of these strains. For 1,393 serovar Typhi strains collected in southern Vietnam, the proportion of multidrug resistance has remained high since 1993 (50% in 2004) and there was a dramatic increase in nalidixic acid resistance between 1993 (4%) and 2005 (97%). In a cross-sectional sample of 381 serovar Typhi strains from 8 Asian countries, Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam, collected in 2002 to 2004, various rates of multidrug resistance (16 to 37%) and nalidixic acid resistance (5 to 51%) were found. The eight Asian countries involved in this study are home to approximately 80% of the world's typhoid fever cases. These results document the scale of drug resistance across Asia. The Ser83-->Phe substitution in GyrA was the predominant alteration in serovar Typhi strains from Vietnam (117/127 isolates; 92.1%). No mutations in gyrB, parC, or parE were detected in 55 of these strains. In vitro time-kill experiments showed a reduction in the efficacy of ofloxacin against strains harboring a single-amino-acid substitution at codon 83 or 87 of GyrA; this effect was more marked against a strain with a double substitution. The 8-methoxy fluoroquinolone gatifloxacin showed rapid killing of serovar Typhi harboring both the single- and double-amino-acid substitutions.

Geographical distribution and risk factors associated with enteric diseases in Vietnam

In Vietnam, shigellosis, typhoid fever, and cholera are important enteric diseases. To determine their magnitude and geographical distribution, and explore associated risk factors, we examined national surveillance data from 1991 to 2001 and potential ecological determinants. Average annual incidence rates were calculated and mapped for each province. Bivariate and multiple regression analyses were used to explore associations with selected environmental and human risk factors. Overall, shigellosis rates per 100,000 population (median, 41; mean, 70) were higher and more widespread than rates for typhoid fever (median, 7; mean, 23) and cholera (median, 0.3; mean, 2.7). Shigellosis was highest in the Central Highlands and was significantly associated with rainfall and urban poverty; typhoid fever prevailed in the Mekong River Delta and was most associated with vapor pressure and river/stream drinking water; and cholera predominated along the Central Coastal regions and correlated positively with rainfall and public well drinking water. The distinct geographical patterns of each disease appear to be driven by a combination of different ecological factors.

Incidence of bacterial meningitis in Asia using enhanced CSF testing: polymerase chain reaction, latex agglutination and culture

To enhance the detection of bacterial meningitis in an East Asian surveillance study, we employed cerebrospinal fluid (CSF) bacterial culture, latex agglutination (LA) and polymerase chain reaction-enzyme immunoassay (PCR-EIA) testing for Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (Sp). The sensitivity and specificity of CSF PCR-EIA testing was compared to LA and culture. A meningitis case was defined by one positive result for any of the three tests. The sensitivity of H. influenzae CSF PCR-EIA, LA, and culture was 100%, 40% and 57.5% respectively; and for Sp CSF PCR-EIA, LA and culture, the sensitivity was 100%, 58.3% and 66.7%, respectively. Hib and Sp specificity was 100% by each method. CSF PCR-EIA was more sensitive than culture or LA for the detection of Hib and Sp meningitis cases increasing their incidence by 74% and 50% compared to culture respectively. CSF PCR-EIA should be included for the detection of bacterial meningitis in surveillance studies.

Safety and immunogenicity of a reformulated Vietnamese bivalent killed, whole-cell, oral cholera vaccine in adults

Vietnam currently produces an orally administered, bivalent (O1 and O139) killed whole-cell vaccine and is the only country in the world with endemic cholera to use an oral cholera vaccine in public health practice. In order to allow international use, the vaccine had to be reformulated to meet World Health Organization (WHO) requirements. We performed a randomized, placebo controlled, safety and immunogenicity studies of this reformulated vaccine among Vietnamese adults. One hundred and forty-four subjects received the two-dose regimen and 143 had two blood samples obtained for analysis. We found that this reformulated oral killed whole-cell cholera vaccine was safe, well tolerated and highly immunogenic.

The feasibility of a school-based VI polysaccharide vaccine mass immunization campaign in Hue City, central Vietnam: streamlining a typhoid fever preventive strategy

We report the coverage, safety, and logistics of a school-based typhoid fever immunization campaign that took place in Hue City, central Vietnam; a typhoid fever endemic area. A cluster-randomized evaluation-blinded controlled trial was designed where 68 schools (cluster) were randomly allocated the single dose Vi polysaccharide vaccine (Typherix) or the active control hepatitis A vaccine (Havrix). A safety surveillance system was implemented. A total of 32,267 children were immunized with a coverage of 57.5%. Strong predictors for vaccination were attending primary schools, peri-urban location of the school, and low family income. Human resources were mainly schoolteachers and the campaign was completed in about 1 month. Most adverse events reported were mild. Safe injection and safe sharp-waste disposal practices were followed. A typhoid fever school-based immunization campaign was safe and logistically possible. Coverage was moderate and can be interpreted as the minimum that could have been achievable because individual written informed consent procedures were sought for the first time in Hue City and the trial nature of the campaign. The lessons learned, together with cost-effectiveness results to be obtained by the end of follow-up period, will hopefully accelerate the introduction of Vi typhoid fever vaccine in Vietnam.

Long-term effectiveness against cholera of oral killed whole-cell vaccine produced in Vietnam

We assessed the long-term protection afforded by a killed whole-cell oral cholera vaccine produced in Vietnam. A mass immunization of children and adults with the killed whole-cell oral cholera vaccine was undertaken in half of the communes of Hue, Vietnam, in 1998; the remaining communes were immunized in 2000. No cholera was observed in Hue until 2003, when an outbreak of El Tor cholera made it possible to conduct a case-control study. The overall vaccine effectiveness 3-5 years after vaccination was 50% (9-63%). This low-cost, easily administered vaccine should be considered as a tool for the control of cholera.

A multi-country cluster randomized controlled effectiveness evaluation to accelerate the introduction of Vi polysaccharide typhoid vaccine in developing countries in Asia: rationale and design

Phase-III vaccine efficacy trials typically employ individually randomized designs intended to ensure that measurements of vaccine protective efficacy reflect only direct vaccine effects. As a result, decisions about introducing newly licensed vaccines into public health programmes often fail to consider the substantially greater protection that may occur when a vaccine is deployed in public health programmes, due to the combination of direct plus indirect vaccine protective effects. Vaccine total protection can be better evaluated with cluster randomized trials. Such a design was considered to generate policy relevant data to accelerate the rationale introduction of the licensed typhoid fever Vi polysaccharide (PS) vaccine in Asia by the Diseases of the Most Impoverished (DOMI) typhoid fever programme. The DOMI's programme multi-country study is one of the largest cluster randomized vaccine trials ever mounted in Asia, which includes approximately 200,000 individuals. Its main objective is to determine the effectiveness of a licensed Vi PS vaccine. The rationale and design of this study are discussed. Preliminary results are presented that determined the final planning of the trial before immunization. Important methodological and practical issues regarding vaccine cluster randomized designs are illustrated.

The burden of rotavirus diarrhea in Khanh Hoa Province, Vietnam: baseline assessment for a rotavirus vaccine trial

BACKGROUND

In Vietnam, rotavirus is seen as a priority disease because studies have demonstrated that >50% of children hospitalized for treatment of diarrhea have rotavirus as the pathogen. To anticipate the availability of new vaccines, we have examined our field area in Nha Trang, Khanh Hoa Province, Vietnam, as a potential site to conduct a field trial of a future rotavirus vaccine.

METHODS

Data from a population census, incidence rates of diarrhea from a previous cholera vaccine trial and hospitalization rates from computerized records collected from the 2 main hospitals in the province were reviewed to estimate the burden of rotavirus-related diarrhea that might be expected during a field trial of a rotavirus vaccine.

RESULTS

For a birth cohort of approximately 5000 children, we would expect approximately 2500 clinic visits and 650-850 hospitalizations for treatment of diarrhea, of which approximately 375-425 would be attributable to rotavirus. For the Vietnamese birth cohort of 1,639,000 children, these numbers translate into approximately 820,000 clinic visits, 122,000-140,000 hospitalizations and 2900-5400 deaths annually attributable to rotavirus-related diarrhea.

CONCLUSIONS

Vietnam is an early adaptor of new vaccines, has high national coverage rates (>85%) for childhood immunization and receives international donor support for the introduction of new vaccines. We found the epidemiologic features of rotavirus in rural Vietnam to be more similar to those of rotavirus in a developed country than to those of rotavirus in India or Bangladesh.

Health Care Costs of Diarrheal Disease and Estimates of the Cost‐Effectiveness of Rotavirus Vaccination in Vietnam

BACKGROUND

Rotavirus disease causes a significant health and economic burden worldwide. Several rotavirus vaccines may soon be available for use. A country's decision to introduce these vaccines will depend on its rotavirus disease burden, on the cost of the vaccine, and on the results of an economic assessment of the cost and effectiveness of a rotavirus vaccination program.

METHODS

Data on medical and nonmedical direct costs and indirect costs were established in Khanh Hoa Province, Vietnam, and extrapolated to national estimates on the basis of the birth cohort in 2004. The main outcome measures were economic burden and cost-effectiveness ratio (United States dollars per disability-adjusted life-year averted and dollars per life saved) of vaccination.

RESULTS

The disease burden is equivalent to an economic burden of an estimated 3.1 million US dollars in medical direct costs, 685,000 US dollars in nonmedical direct costs, and 1.5 million US dollars in indirect costs. From a societal perspective, treatment of rotavirus disease costs an estimated 5.3 million US dollars per year. From the health care system perspective, universal vaccination of infants at a cost of < or = 7.26 US dollars/vaccine dose would be a cost-effective public health intervention, according to the World Bank cost-effectiveness standard for low-income countries (140 US dollars/disability-adjusted life-year).

CONCLUSIONS

Vaccination can effectively reduce the disease burden and health care costs of rotavirus-specific diarrhea in Vietnam.

Epidemiological Profile and Burden of Rotavirus Diarrhea in Vietnam: 5 Years of Sentinel Hospital Surveillance, 1998–2003

For 5 years, we have conducted sentinel surveillance for rotavirus at 6 hospitals in 4 cities in Vietnam. Stool samples obtained from >10,000 children <5 years old who were admitted to the hospital with diarrhea have been screened for rotavirus. Overall, 55% of samples were positive, and there was little variability in rates of detection of rotavirus between sites (44%-62%). In Vietnam, the characteristics of rotavirus infection more closely resemble those seen in developed countries, rather than those seen in developing countries: children become infected at an older age, the percentage of stool samples in which rotavirus is detected is extremely high, and the rotavirus strains appear to be the common types, with fewer mixed infections occurring. It is estimated that 5300-6800 children <5 years old die of rotavirus infection each year in Vietnam, representing 8%-11% of all deaths in this age group (cumulative risk per child by age 5 years, 1 in 200 to 1 in 285). Additional studies are ongoing to document the economic cost of the disease and to assess the burden of both fatal cases and milder cases of disease. Study outcomes will provide information for future testing and potential use of a rotavirus vaccine.