Clinical and virological features of Dengue in Vietnamese infants

Abstract

Background: Infants account for a small proportion of the overall dengue case burden in endemic countries but can be clinically more difficult to manage. The clinical and laboratory features in infants with dengue have not been extensively characterised.

Methodology/principal findings: This prospective, cross-sectional descriptive study of infants hospitalized with dengue was conducted in Vietnam from November 2004 to December 2007. More than two-thirds of 303 infants enrolled on clinical suspicion of dengue had a serologically confirmed dengue virus (DENV) infection. Almost all were primary dengue infections and 80% of the infants developed DHF/DSS. At the time of presentation and during hospitalization, the clinical signs and symptoms in infants with dengue were difficult to distinguish from those with other febrile illnesses, suggesting that in infants early laboratory confirmation could assist appropriate management. Detection of plasma NS1 antigen was found to be a sensitive marker of acute dengue in infants with primary infection, especially in the first few days of illness.

Conclusions/significance: Collectively, these results provide a systematic description of the clinical features of dengue in infants and highlight the value of NS1 detection for diagnosis.

Figure 1. NS1 antigenaemia by disease severity.

Shown are the median, interquartile and 95^th-percentile ranges of log₁₀ NS1 concentration at enrolment, distributed by DENV serotypes and disease severity. Day of illness ranged from 3–9 and was comparable among DF, DHF, DSS groups. The number of patients in each group is shown in italics.

Figure 2. The sensitivity of diagnostic tests in acute DENV infection of infants.

The number of patients evaluated on each day of illness is shown below the graph. Bars show the percentage of samples positive by each assay.