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  • CDC Zika Updates: New Lab Test, MMWR Summaries, Travel Advice for Summer Olympics

    February 26, 2016

    New CDC Laboratory Test for Zika Virus Authorized for Emergency Use by FDA
    Emergency action expected to bolster US laboratory capacity for Zika testing

    In response to a request from the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration (FDA) on February 26 issued an Emergency Use Authorization (EUA) for a diagnostic tool for Zika virus that will be distributed to qualified laboratories and, in the United States, those that are certified to perform high-complexity tests.

    The test, called the CDC Zika IgM Antibody Capture Enzyme-Linked Immunosorbent Assay (Zika MAC-ELISA), is intended for use in detecting antibodies that the body makes to fight a Zika virus infection. These antibodies (in this case, immunoglobulin M, or IgM) appear in the blood of a person infected with Zika virus beginning 4 to 5 days after the start of illness and last for about 12 weeks. The test is intended to be used on blood samples from people with a history of symptoms associated with Zika and/or people who have recently traveled to an area during a time of active Zika transmission.

    The FDA can use the EUA to permit use, based on scientific data, of certain medical products in certain circumstances, including when there is a determination, by the Secretary of Health and Human Services, that there is a significant potential for a public health emergency that has a significant potential to affect national security or the health and security of United States citizens. As there are no commercially available diagnostic tests cleared or approved by the FDA for the detection of Zika virus infection, it was determined that an EUA is crucial to ensure timely access to a diagnostic tool. CDC’s Zika MAC-ELISA is the first diagnostic test authorized for use in the U.S. for the detection of Zika virus during this situation in which there has been a determination that there is a significant potential for a public health emergency that has a significant potential to affect national security or the health and security of United States citizens living abroad and that involves Zika virus.

    Results of Zika MAC-ELISA tests require careful interpretation. A positive test result indicates that a person was likely infected recently with the Zika virus. However, the test can give an incorrect positive. These false-positive results can occur when someone has been infected with another closely related virus (such as dengue virus). When positive or inconclusive results occur, additional testing (plaque reduction neutralization test) to confirm the presence of antibodies to Zika virus will be performed by CDC or a CDC-authorized laboratory.

    Moreover, a negative test result does not necessarily mean that a person has not been infected with Zika virus. If a sample is collected just after a person becomes ill, there may not be enough antibodies for the test to measure, resulting in a false negative. Similarly, if the sample was collected more than 12 weeks after illness, it is possible that the body has successfully fought the virus and antibody levels have dropped below the detectable limit.

    As with any test, it is important that health care providers consult with their patients about test results and the best approach to monitoring their health.

    CDC will begin distributing the test during the next two weeks to qualified laboratories in the Laboratory Response Network (, an integrated network of domestic and international laboratories that can respond to public health emergencies. The test will not be available in U.S. hospitals or other primary care settings. Public health officials anticipate that distribution of the tests will improve laboratory testing capacity for Zika virus in the United States.

    MMWR Synopsis for February 26, 2016

    Zika Virus Infection Among U.S. Pregnant Travelers — August 2015–February 2016

    After reports of microcephaly and other adverse pregnancy outcomes in infants of mothers infected with Zika virus during pregnancy, CDC issued a travel alert on January 15, 2016, advising pregnant women to consider postponing travel to areas with active transmission of Zika virus. On January 19, CDC released interim guidelines for U.S. health care providers caring for pregnant women with travel to an affected area, and an update was released on February 5. As of February 17, CDC had received reports of nine pregnant travelers with laboratory-confirmed Zika virus disease; 10 additional reports of Zika virus disease among pregnant women are currently under investigation. No Zika virus–related hospitalizations or deaths among pregnant women were reported. Pregnancy outcomes among the nine confirmed cases included two early pregnancy losses, two elective terminations, and three live births (two apparently healthy infants and one infant with severe microcephaly); two pregnancies (approximately 18 weeks’ and 34 weeks’ gestation) are continuing without known complications. Confirmed cases of Zika virus infection were reported among women who had traveled to one or more of the following nine areas with ongoing local transmission of Zika virus: American Samoa, Brazil, El Salvador, Guatemala, Haiti, Honduras, Mexico, Puerto Rico, and Samoa. This report summarizes findings from the nine women with confirmed Zika virus infection during pregnancy, including case reports for four women with various clinical outcomes. U.S. health care providers caring for pregnant women with possible Zika virus exposure during pregnancy should follow CDC guidelines for patient evaluation and management. Zika virus disease is a nationally notifiable condition. CDC has developed a voluntary registry to collect information about U.S. pregnant women with confirmed Zika virus infection and their infants. Information about the registry is in preparation and will be available on the CDC website.

    Transmission of Zika Virus Through Sexual Contact with Travelers to Areas of Ongoing Transmission — Continental United States, 2016

    Zika virus infection has been confirmed in three non-travelling women whose only known risk factor was sexual contact with an ill male partner who had recently traveled to an area of ongoing Zika virus transmission. Following publication of CDC’s interim guidance on the prevention of sexual transmission of Zika virus on February 5, 2016, CDC received reports of 14 instances of suspected sexual transmission of Zika virus. Among these, two laboratory-confirmed cases and four probable cases of Zika virus disease have been identified among women who had sexual contact with a male who had traveled to an area of ongoing Zika virus transmission. Two instances have been excluded based on additional information, and six others are still under investigation. State, territorial, and local public health departments, clinicians, and the public should be aware of current recommendations for preventing sexual transmission of Zika virus, particularly to pregnant women. Men who reside in or have traveled to an area of ongoing Zika virus transmission and have a pregnant partner should abstain from sexual activity or consistently and correctly use condoms during sex with their pregnant partner for the duration of the pregnancy.

    CDC Issues Advice for Travel to the 2016 Summer Olympic Games

    On February 26, 2016, CDC issued advice for people planning travel to the 2016 Summer Olympic Games in Rio de Janeiro, Brazil, from August 5 to August 21, 2016, and to the 2016 Paralympic Games scheduled for September 7 to September 18, 2016. These recommendations provide information to travelers to help them take steps to stay safe and healthy during their trips. CDC’s travel guidance for the Olympics covers a variety of health and safety topics, including information about the Zika virus outbreak currently occurring in Brazil. Because of the Zika outbreak, CDC recommends that pregnant women consider not traveling to the Olympics.

    The Zika outbreak in Brazil is dynamic. CDC will continue to monitor the situation and will adjust these recommendations as needed. Current recommendations, based on CDC’s guidance for any area with active Zika transmission, include these:

    Women who are pregnant

    • Consider not going to the Olympics.
    • If you must go to the Olympics, talk to your doctor or healthcare provider first; if you travel, you should strictly follow steps to prevent mosquito bites ( during your trip.
    • If you have a male partner who goes to the Olympics, you may be at risk for sexual transmission of Zika. Either use condoms the right way, every time, or do not have sex during your pregnancy.

    Women who are trying to become pregnant.

    • Before you travel, talk to your health care provider about your plans to become pregnant and the risk of Zika virus infection during your trip.
    • You and your male partner should strictly follow steps to prevent mosquito bites.

    People considering travel should also refer to CDC’s travel notice “Zika Virus in South America” for additional information:

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