Assessment of the factors associated with flavivirus seroprevalence in a population in Southern Vietnam

Abstract

Dengue and Japanese encephalitis flaviviruses cause severe disease and are hyperendemic in southern Vietnam. This study assesses associations between sociodemographic factors and flavivirus seroprevalence in this region. Sera were collected from 308 community and hospital-based subjects between April 1996 and August 1997 and tested with an indirect ELISA. The factors associated with seroprevalence were assessed using multivariate logistic regression. In this first report of adjusted prevalence odds ratios (POR) for flavivirus infection in Vietnam, seropositivity was associated with increasing age in children (multiple regression coefficients for a child compared to an adult = -4.975 and for age in children = 0.354) and residence in the city compared to surrounding rural districts. The association with age indicates that subjects were most likely to have acquired infection in early childhood. This is key to the design of Vietnamese health education and immunization programmes.

Dengue Virus Infections and Maternal Antibody Decay in a Prospective Birth Cohort Study of Vietnamese Infants

“…Among the population of women we studied, almost all (98%) had serological evidence of previous DENV infection, consistent with high seroprevalence in southern Vietnam [13, 14]. As in other studies [12, 16, 17], we found that total IgG and anti-DENV antibody titers were higher in cord blood than corresponding maternal titers.…”

“…The incidence of DENV infection in this cohort was 1.7 cases per 100 person-years (95% CI, 0.8–3.2 cases per 100 person-years), a substantially lower exposure rate than that reported for older children in Vietnam [13, 14]. Furthermore, our results suggest the vast majority of DENV infections in infants are likely to be asymptomatic.…”

“…The only previous prospective cohort study of infants <1 year of age demonstrated an infection incidence rate of ~2 cases per 100 person-years [12]. In southern Vietnam the annual exposure risk in children is ~10% per annum [13, 14], but the exposure risk in infants is unknown. A better understanding of the epidemiology of dengue in infants and the incidence of symptomatic illness will help guide decisions as to when dengue vaccines should be introduced to endemic regions.…”

The Influence of Urbanization Modes on the Spatial Circulation of Flaviviruses within Ouagadougou (Burkina Faso)

“…Moreover, lack of householder’s education was associated with past flavivirus infection, as often observed in the health field [34]. Similarly, the absence of links between flavivirus seroprevalence and socio-economic level confirmed previous results [35]. …”

Epidemiology and Etiology of Acute Encephalitis Syndrome in North India

“…The attack rates are 5-10 times lower in adults (À15 years) than in children (3-15 years) (4). Similarly, the association of other flaviviral infections with age indicates that early childhood is the most susceptible age for these infections (26). Mumps was found to predominantly affect older teens and young adults, which include the unvaccinated population; this population has probably not developed immunity through exposure to the mumps virus because of decreased circulation of the virus after the implementation of childhood immunization program (27).…”