CDC on Monday issued new guidance for health care providers caring for pregnant women who may have been exposed to the Zika virus, the Washington Post's "To Your Health" reports.
At least 400 pregnant women in U.S. states and the District of Columbia, and at least 378 pregnant women in U.S. territories, have contracted Zika (Sun, "To Your Health," Washington Post, 7/25).
Background on Zika virus
The Zika virus is not easily diagnosed, and it does not have a cure or vaccine. It is linked to the birth defect microcephaly, a condition in which an infant is born with an abnormally small head and brain. The condition is fatal for some infants, while others experience permanent disabilities.
The virus is most commonly transmitted by a bite from an infected mosquito, but it can also spread through sexual activity.
Earlier this month, Congress left for a seven-week recess without sending President Obama legislation to fund a response to the Zika virus. Existing funding for Zika response efforts is expected to run out in late July or early August, according to HHS Secretary Sylvia Mathews Burwell (Women's Health Policy Report, 7/18).
New guidance
The updated CDC guidance applies to both pregnant women who show symptoms of Zika infection and those who have not shown symptoms of contracting the virus ("To Your Health," Washington Post, 7/25). According to the latest guidance, a physician should ask a pregnant woman whether she or her sex partner has traveled to an area affected by Zika (Stobbe, AP/Sacramento Bee, 7/25).
In addition, according to the agency, pregnant women who have potentially been exposed to Zika should be tested for the virus up to two weeks after they first experience symptoms. Previously, CDC recommended that pregnant women be tested within seven days of the onset of symptoms. With the extended window, CDC officials hope to be able to detect more cases of Zika in pregnant women ("To Your Health," Washington Post, 7/25).
CDC officials said the update comes in response to data that suggest Zika virus RNA can be detected in some pregnant women for extended periods (Oduyebo et al., Morbidity and Mortality Report, 7/25). Scientists previously believed that if a person contracted Zika, the virus would remain in the bloodstream for about seven days after symptoms begin. In turn, that seven-day period was considered the best window to administer a test that detects Zika virus.
However, another test that checks whether someone has been infected with a virus in the family that encompasses Zika is typically administered more than seven days after the onset of symptoms. While researchers may not be able to make a specific diagnosis based off of the broader test, a pregnant woman who tests positive on that test could be offered the Zika-specific test to verify a diagnosis, according to the guidance.
In addition, CDC has updated its guidelines for safe sex practices for avoiding Zika infection among pregnant women. CDC now recommends that all pregnant women who have traveled to or live in a Zika-affected area abstain from sex or use condoms for the remainder of their pregnancy. The recommendation applies regardless of the sex of the pregnant woman's sexual partner ("To Your Health," Washington Post, 7/25).
The update comes after the first case of female-to-male sexual Zika transmission was recorded earlier this month. Previously, researchers had only documented Zika transmission from an infected male partner to a female partner (Women's Health Policy Report, 7/18).
Study projects up to 1.65M cases of Zika in reproductive-age women
In related news, up to 1.65 million reproductive-age women in Central and Latin America could contract Zika during the first two to three years of the outbreak, according to a study published Monday in Nature Microbiology, Reuters reports.
Researchers made the projections using an enhanced model of the Zika outbreak, according to Reuters. In making their projections, the researchers accounted for prior outbreaks of viruses similar to Zika, mosquito transmission patterns, the state of the climate, viral incubation periods, the effect of herd immunity and the possible effect of economic conditions. Other Zika modeling efforts have been complicated by the fact that people infected with the virus may not show symptoms.
Key findings
Based on the projection of 1.65 million cases of Zika infection among reproductive-age women, the researchers said there could be tens of thousands of cases of Zika-related fetal anomalies. According to the study, Brazil is projected to see triple the number of Zika infections of any other country because of the size of the country and other characteristics that increase its potential for virus transmission.
Study coauthor Alex Perkins of the University of Notre Dame said the projection of 1.65 million cases "is a cumulative number over the course of roughly the first two to three years of the outbreak." He added, "We consider that to be an upper limit of what might be possible." Perkins noted that women in low-income communities have a higher risk of contracting the virus because they are less likely to have window screens and air conditioners. Window screens and air conditioners considerably reduce exposure to Zika-carrying mosquitos, he said (Steenhuysen, Reuters, 7/25).
Colombia declares Zika epidemic over
In other related news, health officials in Colombia on Monday announced that the country's Zika epidemic has ended, the New York Times reports.
According to health officials, the number of new Zika infections in Colombia has dropped to 600 new cases weekly. Health officials expect there will be a limited number of new cases reported over the next few months, although Deputy Health Minister Fernando Ruiz Gómez noted that the timeframe during which the virus "will remain local still hasn't been determined."
About 100,000 individuals in Colombia have contracted Zika, including nearly 18,000 pregnant women. So far, the virus has been linked to over 20 cases of microcephaly in the country.
Ruiz Gómez said he expects there will be a surge of microcephaly cases in September and October when pregnant women who were infected with the virus during the epidemic deliver their infants. Colombia allows abortion only under certain circumstances (Casey, New York Times, 7/25).
