Age-Specificity of Clinical Dengue during Primary and Secondary Infections

Abstract

BackgroundThis study aims to estimate the age-specific risks of clinical dengue attack (i.e., the risk of symptomatic dengue among the total number of dengue virus (DENV) infections) during primary and secondary infections.MethodsWe analyzed two pieces of epidemiological information in Binh Thuan province, southern Vietnam, i.e., age-specific seroprevalence and a community-wide longitudinal study of clinical dengue attack. The latter data set stratified febrile patients with DENV infection by age as well as infection parity. A simple modeling approach was employed to estimate the age-specific risks of clinical dengue attack during primary and secondary infections.ResultsUsing the seroprevalence data, the force of infection was estimated to be 11.7% (95% confidence intervals (CI): 10.8–12.7) per year. Median age (and the 25–75 percentiles) of dengue fever patients during primary and secondary infections were 12 (9–20) and 20 (14–31) years, respectively. The estimated age-specific risk of clinical dengue increases as a function of age for both primary and secondary infections; the estimated proportion of symptomatic patients among the total number of infected individuals was estimated to be <7% for those aged <10 years for both primary and secondary infections, but increased as patients become older, reaching to 8–11% by the age of 20 years.Conclusions/SignificanceFor both primary and secondary infections, higher age at DENV infection was shown to result in higher risk of clinical attack. Age as an important modulator of clinical dengue explains recent increase in dengue notifications in ageing countries in Southeast Asia, and moreover, poses a paradoxical problem of an increase in adult patients resulting from a decline in the force of infection, which may be caused by various factors including time-dependent variations in epidemiological, ecological and demographic dynamics.

A Study of Multiorgan Dysfunction in Patients With Dengue and Its Clinico- Haematological Correlation With Severity.

“…The male predominance has also been reported in several other studies [6]. The mean age of patients in our study was 32.4 years which is similar to other studies where higher age groups were observed of developing symptomatic disease than younger groups [7][8][9] and contradictory to the study by Raut and Patil where they revealed children <10 years were affected more [10].…”

Retrospective Analysis of Demographic and Clinical Profile of Dengue Infection in a Tertiary Care Hospital

“…The incidence of dengue was least in the older age groups probably in our view because of lesser outdoor activity compared to younger people. This was similar to a study performed by Amir Khan et al (5).n a study by Khoa T.D.Thai et al (6) showed that increasing age lead to increasing risk of clinical attack in both primary and secondary dengue infection. This study was done by obtaining seroprevalence of dengue specific for age and frequency of clinical attack specific for age.…”

Forty Years of Dengue Surveillance at a Tertiary Pediatric Hospital in Bangkok, Thailand, 1973–2012

“…There are several plausible, nonmutually exclusive explanations for the decreasing severity over time. A difference in disease severity with age is a phenomenon that has been noted previously, for example, in Cuba, Thailand, and Singapore, [19][20][21][22][23] which could be consistent with the observed trends; however, we do not observe such a clear relationship with age and severity here and observe a fairly small shift in age of cases. Secondly, in 1999, a new handbook was published with recommendations for hospitalization of suspected dengue cases.…”