The latest on testing guidelines for Zika from the CDC. Plus: Are corticosteroids effective when administered only hours before delivery? Also, a look at the prevalence of hepatitis C among pregnancy women in the United States.
New data on persistence of Zika virus in some infected individuals has led The Centers for Disease Control and Prevention (CDC) to issue an update on testing of asymptomatic pregnant women. The health advisory builds on interim guidance for health care providers that was published by CDC in July 2016.
Emerging epidemiologic and laboratory data, said CDC, indicate that Zika virus IgM can persist beyond 12 weeks in a subset of infected people. As a result, IgM detection may not always indicate a recent infection. A Puerto Rican study of symptomatic patients with nucleic acid test (NAT)-confirmed Zika shows persistence of the virus IgM in 100% of participants at 8 to 15 days after symptom onset and in 87% at more than 60 days after symptom onset. Median time to first negative Zika virus IgM was 4 months (range 8-210 days) according to unpublished data from the ongoing study.
CDC noted that while IgM persistence could affect test interpretation in all patients infected with Zika, it would have the greatest effect on clinical management of pregnant women with a history of living in or traveling to areas with Zika virus transmission before conception. Pregnant women who test positive for IgM antibody may have been infected with the virus and developed the response before conception.
CDC’s recommendations for testing symptomatic pregnant women are unchanged. For asymptomatic pregnancy women who live in or frequently travel to areas with Zika virus transmission with CDC Zika Travel Notices, the agency recommends:
· Screening for risk of Zika exposure and symptoms, with prompt NAT testing if symptoms develop during pregnancy or a sexual partner tests positive for Zika;
· Consideration of NAT testing at least once per trimester, unless a previous test has been positive;
· Consideration of NAT testing of amniocentesis specimens if the test is performed for other reasons;
· Patient counseling each trimester on limitations of IgM and NAT testing; and
· Consideration of IgM testing to determine baseline Zika virus IgM levels as part of preconception counseling.
Can corticosteroids be effective hours before delivery?
Administering antenatal corticosteroids only hours prior to delivery may improve survival in very preterm infants, according to results of a Swedish study published in JAMA Pediatrics.
Researchers used data from the Effective Perinatal Intensive Care in Europe study, which gathered information from 19 regions across 11 European countries from 2011 to 2013. The cohort included 4594 singleton infants with a gestational age range of 24 to 31 weeks. The infants did not have severe anomalies and were not otherwise exposed to multiple courses of antenatal corticosteroids. The authors studied 3 outcomes: severe neonatal brain injury, which was defined as an intraventricular hemorrhage grade 3 or greater or cystic periventricular leukomalacia; composite of mortality or severe neonatal morbidity, which was defined as an intraventricular hemorrhage grade of 3 or greater, cystic periventricular leukomalacia, surgical necrotizing enterocolitis, or stage 3 or greater retinopathy of prematurity; and in-hospital mortality.
Of the infants in the cohort, 2496 were boys. The average gestational age was 28.5 weeks and the average birth weight was 1213 g. Among the 662 infants unexposed to antenatal corticosteroids, the mortality rate was 20.6% (136 of 661). Administering antenatal corticosteroids was linked with a rapid and immediate decline in mortality, which plateaued with over 50% risk reduction where administration-to-birth interval was 18 to 36 hours. A similar pattern was seen for composite mortality or morbidity outcome. An administration-to-birth interval of more than 48 hours was linked with a significant reduction in the risk of severe neonatal brain injury. The risk reduction association was antenatal corticosteroids was transient and an administration-to-birth interval exceeding 1 week was associated with increasing mortality and risk of severe neonatal brain injury.
Based on the assumption that a causal relationship existed between mortality and timing of antenatal corticosteroids, the researchers performed a simulation which demonstrated that administering the drugs 3 hours before delivery to infants who had no previous exposure was associated with an estimated decline in mortality of 26%. They concluded that, contrary to previous hypotheses, administration of antenatal corticosteroids in a few hours prior to delivery may prove effective for improving survival and decreasing neonatal morbidity in very preterm infants.
Is hepatitis C on the rise in pregnant women?
According to a recent report from the Centers for Disease Control and Prevention, the rate of hepatitis C is on the rise in the United States among women giving birth.
Investigators used US birth certificate data to examine trends and geographic differences in the rates of hepatitis C infection among women who gave birth between 2009 and 2014. They used Tennessee birth certificates to examine individual characteristics and outcomes linked with a hepatitis C infection and a multivariable model to calculated adjusted odds. The data were collected from the National Vital Statistics System and Tennessee Department of Health vital records.
During the study period, presence of a hepatitis C infection at time of delivery from states reporting such infections on birth certificates increased by 89%, from 1.8 to 3.4 per 1000 live births. The highest infection rate in 2014 was found in West Virginia, at 22.6 per 1000 live births, while Hawaii had the lowest rate at 0.7 per 1000 live births. In the adjusted analyses of Tennessee births, where the rate is 10.1 per 1000 live births, the odds of having a hepatitis C infection were roughly 3-fold higher among women who lived in rural counties than in those who lived in urban counties. In women who smoked cigarettes while pregnant, the odds of an infection were 4.5-fold higher, and among women who had a concurrent hepatitis B infection, the odds were 17-fold higher.
The implications for public health practice from these data are that screening for hepatitis C in women who are of childbearing age and providing treatment may help reduce perinatal transmission of the disease. Monitoring infants who are exposed to hepatitis C also could aid in identifying these infections.