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Resumen de Conferencias Internacionales (CI)

ZIKA VIRUS IN BRAZIL: FROM INTRODUCTION TO THE
CI­06 DEVELOPMENT OF VACCINE CANDIDATE

Pedro Fernando da Costa Vasconcelos

Department of Arbovirology and Hemorrhagic Fever, Instituto Evandro Chagas,
Ananindeua, Brazil and Department of Pathology , Universidade do estado do
Pará, Belém, Brazil

Zika virus (ZIKV) was identified in Brazil in April 2015 and that time it was
associated with a febrile dengue­like illness in northeast region of country. It was
isolated and genetic studies using samples from different geographic region
suggested an introduction in Brazil in 2013, possible following the Confederation
Cup of Soccer. After introduction, the spread was so fast, possibly due to the
high density of Aedes aegypti vectors in the country and also due to non­
vectored transmission, especially sexual transmission. In the second half of 2015
and in 2016, Brazil (and other Latin America countries) suffered an important
epidemic of microcephaly and other birth defects that were originally
characterized by the Instituto Evandro Chagas as caused by ZIKV. Several
deaths of microcephalic neonates were investigated and ZIKV was isolated and
detected by real­time RT­PCR (RT­qPCR) confirming the ZIKV as causal agent
of the cases. Several studies were performed later and confirmed ZIKV as the
causal agent of the neonate birth defects now characterized as Zika Congenital
Syndrome (ZCS). ZCS has been documented in hundreds of cases in Brazil, and
in several Latin American countries. Particularly in Brazil, the number of cases
were concentrated in the northeast region and in Rio de Janeiro state (southeast
region), but sporadic ZCS cases were confirmed in almost all Brazilian
geographic regions. Efforts for the development of ZIKV vaccine was performed
at many different scientific institutions. An initiative was carried out by the
University of Texas medical Branch (UTMB) and the Instituto Evandro Chagas
(IEC) with financial support of the Brazilian Ministry of Health. A live attenuated
ZIKV vaccine was developed and pre­clinical studies showed the vaccine to be
capable to prevent ZIKV transmission to mice (including pregnant mice) and non­
human primates (Rhesus monkey). Clinical trials will be conducted by Oswaldo
Cruz Foundation at Rio de Janeiro, in order to demonstrate in human its
antigenicity, immunogenicity and degree of protection of ZIKV infection and
transmission in children under 10 years old.

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