In a sign that sexual transmission of Zika virus may occur more often than currently thought, the US Centers for Disease Control and Prevention (CDC) said today it is investigating 14 new reports of possible transmission through that route.
The development underscores earlier advice that people returning from outbreak areas take strict safe-sex precautions, the CDC said.
Zika confirmed in 2 cases
The CDC said that several of the possible sexual transmission cases it and state health department partners are investigating involve pregnant women, the group at highest risk in the outbreak.
Investigations into the 14 possible cases are at various stages. In two instances, Zika infections have been confirmed in women whose only known exposure was sexual contact with a sick man who had recently traveled to an area where the virus is circulating. Tests results on their male partners are pending.
In four other women, preliminary antibody tests are positive, and confirmation tests are under way. For the eight other suspected cases, investigations are ongoing.
For all of the cases with available information, travelers were men who had Zika virus symptoms 2 weeks before their nontraveling female partners became ill. The CDC said that, as with earlier reported sexual transmission cases, the new suspected cases involve transmission from men to their sex partners.
"At this time, there is no evidence the women can transmit Zika virus to their sex partners; however, more research is needed to understand the issue," the CDC said.
The agency repeated that mosquito bites are still the primary way the virus transmits, and the best way to prevent infection is to avoid mosquito bites. Given the new findings, however, it issued a Health Alert Network (HAN) advisory to remind the public of its Feb 5 interim guidance on safe-sex precautions for Zika virus.
Expanded travel warning
In other domestic developments, the CDC today added two more travel destinations—Trinidad and Tobago and the Marshall Islands—to its Zika virus travel advisory.
The CDC first issued stepped-up guidance on Jan 15, urging pregnant women and those planning on becoming pregnant to postpone travel to countries and territories where the virus is circulating. As the reach of the virus has expanded, the CDC has updated its travel guidance several times to include more destinations.
Emergency funding request
President Barack Obama yesterday formally requested from Congress nearly $1.9 billion in emergency funding to assist with domestic and international Zika virus response actions. In a letter to House speaker Paul Ryan, R-Wisc., the president also requested transfer authority to address changing circumstances and changing needs as the outbreak evolves.
Details from the Office of Management and Budget on how the funds would be spent that were included in the letter said the request would also provide flexibility on the use of remaining Ebola funds at the US Agency for International Development.
Feb 23 CDC press release
Feb 23 CDC HAN advisory
Feb 22 White House letter