(This post has been updated.)
Nine women who live in the United States but traveled where Zika virus is spreading became infected while pregnant, and 10 others who are pregnant are being watched, the Centers for Disease Control said Friday afternoon. Of the nine pregnancies, two ended in miscarriage; two women chose abortions; two are still pregnant; and three delivered, two with apparently healthy infants and one with a child with microcephaly.
Meanwhile, despite warnings to use protection or abstain, Zika is being transmitted sexually by men who have traveled to the infectious zone to people who have not left the country. There are 14 possible such cases, including two confirmed and four probable cases among women infected by men, the agency said.
“We did not expect to see these brain abnormalities in this small case series,” Dr. Denise J. Jamieson, a leader in the pregnancy and birth defects group of the CDC’s Zika Virus Response Team, told reporters in a phone briefing. “It is unexpected and greater than we would have expected.”
But there is not yet enough data to calculate what the risk of having an affected child is, Dr. Tom Frieden, the CDC’s director, said in the same phone briefing. He added that the agency anticipated “hundreds or even thousands” of infections in travelers returning from affected areas, but “we did not anticipate we would see this many sexually transmitted cases of Zika.”
The agency disclosed a limited number of details about some of the cases in the phone call and in two papers placed on the website of its weekly bulletin, the Morbidity and Mortality Weekly Report. But it was conservative with what it shared. The CDC refused to say whether the single infant born with microcephaly is the child born in Hawaii in December, declined to associate any of the remaining pregnancies with news reports of pregnant women being diagnosed with Zika in Illinois and Florida, and would not comment on whether an Oregon case of sexual transmission announced earlier Friday is among their count. (It also did not address to what degree sexual transmission is occurring among male couples.)
So far, 257 women have asked to be tested for Zika, but only nine have been confirmed infected. The agency, which has warned pregnant women not to travel to 34 countries and territories so far, estimates that about 500,000 women each year travel to the US from the Zika zone.
Among the cases the CDC reported Friday, women who developed the symptoms of Zika—fever, rash, aches, eye irritation—in their first trimester were worst affected.
- Out of the six pregnant women apparently infected in their first trimester, two experienced miscarriages, one at 8 weeks after developing Zika symptoms in her 6th week. Two chose abortions, one after confirming brain abnormalities in her fetus by medical imaging at 20 weeks. One delivered a 39-week-old child with microcephaly, and one is still pregnant.
- Of two women who experienced Zika symptoms in their second trimester, one delivered a healthy child at 40 weeks and one is still pregnant.
- One woman who told the CDC she experienced Zika symptoms in her third trimester also delivered a healthy child, but the agency did not provide any other details.
All of the women had traveled somewhere in the Zika zone: American Samoa, Brazil, El Salvador, Guatemala, Haiti, Honduras, Mexico, Puerto Rico, or Samoa.
The CDC also released new numbers of US residents who have contracted Zika. As of Wednesday, there have been 107 cases of Zika in 24 states and Washington, DC in people who traveled to countries where the virus is circulating, and 40 cases in Puerto Rico, the worst-hit of the US island territories.
Update: Late Friday, the CDC also released a statement warning women who are pregnant that they should not attend the 2016 Olympics in Brazil—a warning that was expected, given the CDC’s advice that pregnant women not travel to so many countries in the Zika zone, but also had been tensely waited for given the obvious political sensitivity. If women who are pregnant or trying to get pregnant have male partners attending the Olympics, the CDC counseled them to avoid sex during the rest of the pregnancy or use condoms for any sex act.