Neutralizing Dengue Antibody in Pregnant Thai Women and Cord Blood

<div><p>Background</p><p>The WHO ‘Global Strategy for Dengue Prevention and Control, 2012–2020’ addresses the growing need for the treatment of dengue, and targets a 25% reduction in morbidity and 50% in mortality (using 2010 estimates as baseline). Achieving these goals requires future dengue prevention strategies that will employ both potential vaccines and sustainable vector-control measures. Maternally transferred dengue antibody is an important factor in determining the optimal age for dengue vaccination.</p><p>Objectives</p><p>To estimate the seroprevalence of dengue antibodies among mothers living in an area of high endemicity – Ban Pong, Ratchaburi Province – and to assess maternal dengue antibodies transferred to cord blood.</p><p>Materials & Methods</p><p>A cross-sectional study was conducted with 141 pregnant women who delivered at Ban Pong Hospital, Ratchaburi, Thailand. Maternal-cord paired sera were tested for dengue neutralizing (NT) antibody by PRNT₅₀ assay. A ratio of ≥ 1:10 NT titer to dengue serotype was considered seropositive.</p><p>Results</p><p>Most mothers (137/141, 97.2%) had NT antibodies to at least one dengue serotype in their sera. At birth, the proportion of cord sera with NT antibodies to DEN-1, DEN-2, DEN-3, and DEN-4, were high and similar to the sera of their mothers, at 93.6%, 97.2%, 97.9%, and 92.2%, respectively. The dengue geometric mean titers (GMT) in cord blood were significantly higher than the maternal antibodies (p<0.001): highest in DEN-2, followed by DEN-3, and then DEN-1. The GMT of DEN-4 was the lowest among all four serotypes.</p><p>Conclusions</p><p>Dengue infection is highly prevalent among pregnant women in this dengue-endemic area. Most of the cord blood had transferred dengue antibodies, which may have an impact on the disease burden in this population.</p></div

The proportion and geometric mean titer of NT dengue antibodies of 141 maternal and cord paired sera.

<p>Note: p-values for comparisons of seroprevalence are based on symmetry test; p-values for comparisons of GMTs between mother and cord are based on paired test of log (NT)</p><p>The proportion and geometric mean titer of NT dengue antibodies of 141 maternal and cord paired sera.</p

Demographic characteristics of 141 pregnant women.

<p>Demographic characteristics of 141 pregnant women.</p

Correlation between maternal and cord blood of DEN-1 to DEN-4 neutralizing antibodies titers.

<p>X-axis shows GMTs of cord blood dengue antibody and Y-axis shows GMTs of maternal dengue antibody of DEN-1, DEN-2, DEN-3 and DEN-4. The Spearman’s rho of DEN1, DEN2, DEN3 and DEN4 are 0.90, 0.92, 0.88 and 0.89 respectively.</p

Comparison of maternal dengue seroprevalence, maternal and cord sera dengue antibody titers in various articles.

<p>* p-values are based on paired sample t-test</p><p>^a range</p><p>^b mean±SD</p><p>^c mg/dL, GMT (range)</p><p>^d p-value 0.002 for DEN-1, 0.003 for DEN-3 and <0.001 for DEN-2 and DEN-4</p><p>^e p-value <0.001 for DEN-2 and DEN-3 only, p-value for DEN-1 and DEN-4 ≥ 0.5</p><p><i>n/a</i> = not applicable, <i>n</i>.<i>d</i>. <i>=</i> no data available</p><p>Comparison of maternal dengue seroprevalence, maternal and cord sera dengue antibody titers in various articles.</p