Source:
Centers for Disease Control and Prevention. 13 April 2016
Scientists at the Centers for Disease Control and Prevention
(CDC) have concluded, after careful review of existing evidence,
that Zika virus is a cause of microcephaly and other severe fetal
brain defects. In the report published in the New England Journal
of Medicine, the CDC authors describe a rigorous weighing of
evidence using established scientific criteria.
"This study marks a turning point in the Zika outbreak. It
is now clear that the virus causes microcephaly. We are also
launching further studies to determine whether children who have
microcephaly born to mothers infected by the Zika virus is the tip
of the iceberg of what we could see in damaging effects on the
brain and other developmental problems," said Tom Frieden,
M.D., M.P.H., director of the CDC. "We've now confirmed what
mounting evidence has suggested, affirming our early guidance to
pregnant women and their partners to take steps to avoid Zika
infection and to health care professionals who are talking to
patients every day. We are working to do everything possible
to protect the American public."
Background
The report notes that no single piece of evidence provides
conclusive proof that Zika virus infection is a cause of
microcephaly and other fetal brain defects. Rather, increasing
evidence from a number of recently published studies and a careful
evaluation using established scientific criteria supports the
authors' conclusions.
The finding that Zika virus infection can cause microcephaly and
other severe fetal brain defects means that a woman who is infected
with Zika during pregnancy has an increased risk of having a baby
with these health problems. It does not mean, however, that all
women who have Zika virus infection during pregnancy will have
babies with problems. As has been seen during the current Zika
outbreak, some infected women have delivered babies that appear to
be healthy.
Establishing this causal relationship between Zika and fetal
brain defects is an important step in driving additional prevention
efforts, focusing research activities, and reinforcing the need for
direct communication about the risks of Zika. While one important
question about causality has been answered, many questions remain.
Answering these will be the focus of ongoing research to help
improve prevention efforts, which ultimately may help reduce the
effects of Zika virus infection during pregnancy.
At this time, CDC is not changing its current guidance as a
result of this finding. Pregnant women should continue to avoid
travel to areas where Zika is actively spreading. If a pregnant
woman travels to or lives in an area with active Zika virus
transmission, she should talk with her healthcare provider and
strictly follow steps to prevent mosquito bites and to prevent
sexual transmission of Zika virus. We also continue to encourage
women and their partners in areas with active Zika transmission to
engage in pregnancy planning and counseling with their health care
providers so that they know the risks and the ways to mitigate
them.