CDC: Zika pregnancies 20 times more likely to result in birth defects
The Washington Post
Pregnancies of women in the U.S. infected with the Zika virus are about 20 times more likely to result in babies with certain birth defects compared to the prevalence of these birth defects before the Zika epidemic swept through the Americas, according to a report released Thursday.
Researchers at the Centers for Disease Control and Prevention are trying to determine how common these birth defects, such as microcephaly, brain abnormalities, eye defects and central nervous system problems, were in the years before the outbreak. Although a Zika infection during pregnancy is linked to a distinct pattern of birth defects, genetic factors and other viral infections may also cause these birth defects. In many cases the causes are unknown, experts say.
The CDC concluded last April that Zika infection caused birth defects, including the abnormally small heads of microcephaly, but it had not previously estimated how common the defects were.
The CDC report provides a baseline reference to interpret the impact of Zika on the prevalence of these birth defects in the U.S. The new data underscore the dangers of Zika infection during pregnancy and the advice that pregnant women should avoid travel to Zika-affected areas. If that’s not possible, they should take measures to prevent mosquito bites or sexual transmission of the virus.
The magnitude of birth defect risks also underlines the critical importance of early and accurate testing for pregnant women to give them the full range of options, health care providers say.
In Washington, D.C., the district’s public-health lab has produced erroneous or inconclusive results for nine and perhaps more pregnant women who were tested for Zika between July and December of last year. The lab reported that the women had tested negative for Zika, when they may in fact have been infected. The mistakes, made public Feb. 16, have prompted officials to redo more than 400 tests.
Researchers analyzed birth defects from three surveillance programs in the U.S. They identified 747 infants and fetuses with one or more of the defects from data collected in Massachusetts, North Carolina and Georgia. The prevalence was about 3 for every 1,000 births between 2013 and 2014. The defects included the entire range of abnormalities associated with Zika.
The proportion of infants with those birth defects was about 6 percent, or nearly 60 out of every 1,000 completed pregnancies with Zika infections. This proportion is about 20 times higher than the prevalence of such birth defects during the pre-Zika years.
The CDC has awarded over $27 million to 50 jurisdictions to establish or bolster surveillance systems that rapidly collect information about Zika-related birth defects. On Thursday, Florida health officials reported three more cases of the virus that were locally acquired in MiamiDade — two infections dating to October 2016 and the first one of 2017.