Preliminary Report of Microcephaly Potentially Associated with Zika Virus Infection During Pregnancy — Colombia, January–November 2016

Abstract

© 2016, Department of Health and Human Services. All rights reserved. What is already known about this topic? Zika virus infection during pregnancy can cause microcephaly and serious brain abnormalities in fetuses and infants exposed in utero. The Zika virus disease outbreak in the World Health Organization’s Region of the Americas began in Brazil, which first reported a laboratory-confirmed Zika virus outbreak in May 2015; Colombia confirmed local transmission of Zika virus about 5 months later, in October 2015. Colombia’s Instituto Nacional de Salud maintains national surveillance for birth defects, including microcephaly. What is added by this report? This report provides preliminary national birth defects surveil­lance data on congenital microcephaly following a large outbreak of Zika virus infection in Colombia. Microcephaly prevalence increased more than fourfold overall in 2016 compared with 2015, with a ninefold increase in July 2016 (the peak month) compared with July 2015. The temporal association between Zika virus infections and microcephaly, with the peak of reported microcephaly occurring approximately 24 weeks after the peak of the Zika outbreak, provides evidence that the greatest risk period is likely the first trimester of pregnancy and early in the second trimester of pregnancy. What are the implications for public health practice? Colombia has experienced a significant increase in congenital microcephaly in 2016 following the peak of the Zika virus disease outbreak. Ongoing population-based birth defects surveillance is essential for monitoring the impact of Zika virus infection during pregnancy on birth defects prevalence and measuring the success in preventing Zika virus infection and its consequences, including microcephaly.