Analysis of Dengue and Zika Antibodies Among a Cohort of Pregnant Women in Salvador, Brazil

Abstract

Dengue virus has been circulating in a hyperendemic pattern in Brazil for decades and the introduction of Zika virus, a closely related member of the flavivirus genus, into the Americas has complicated this situation. Zika virus has only recently begun to be viewed as a pathogen of significant concern. A dramatic increase in the incidence of microcephaly in Northeastern Brazil was reported in late 2015, coinciding with a large increase in ZIKV infection. This unique pattern of microcephaly and other disabilities linked to infection with the Zika virus during pregnancy is known as Congenital Zika Syndrome (CZS). The pathogenesis driving this phenomenon is unknown, however, due to the similarities between Zika and dengue viruses, it is theorized that dengue virus-mediated immune enhancement in mothers may be a risk factor for the development of CZS in infants. As such, it is important to further study the immune profiles of pregnant women infected with dengue and Zika viruses. Our research analyzes the antibody response to dengue and Zika viruses among pregnant women during the 2015-16 Zika outbreak in Salvador, Brazil, and characterizes cross-reactive antibodies between dengue (DENV) and Zika (ZIKV). This study provides the unique ability to study the background levels of dengue virus immunity in pregnant women in Northeast Brazil at the time of the ZIKV epidemic. Much is unknown about the effect of prior dengue infection and its ability to confer protection or risk of enhancement of Zika virus infection, especially during pregnancy. We aim to better understand this relationship and how it correlates to protection, with the long-term goal of facilitating the development of safe and effective DENV and ZIKV vaccines.