Zika on the ground: Clinical impact update

March 9, 2016

An update on the Zika virus and its impact on your practice. And, a look at whether or not vaginal delivery increases risk of incontinence. Plus: What was the impact of the HPV vaccine on HPV rates?

Two new reports-one by the Centers for Disease Control and Prevention (CDC) and another a case report of a third-trimester fetal demise-are helping to bring into increased focus the potential clinical impact of Zika virus. Published in MMWR, the CDC data provide perspective on testing for the virus in pregnant women who have traveled to endemic areas. The case report, published in PLOS Neglected Tropical Diseases, suggests a linkage between Zika and hydrops fetal and fetal demise.

More: Pregnant women and Zika exposure

The MMWR report is an analysis of requests to CDC for testing for Zika virus by pregnant women between August 1, 2015 and February 10, 2016. Of the 257 pregnant women who made such requests during that period, 151 (59%) had two or more signs or symptoms consistent with Zika (i.e. acute onset of fever, rash, conjunctivitis, or arthralgia.). None of the women had Zika-related hospitalizations or deaths.

Two of the pregnancies resulted in early loss and 2 were electively terminated. As of the report, 2 pregnancies, at 18 and 34 weeks’ respectively, were continuing with no known complications. Of the 3 babies born alive to the women tested, 2 are apparently normal and 1 has severe microcephaly. Both of the healthy infants are the offspring of women who had symptoms of Zika virus infection during pregnancy, one in the second trimester and the other in the third trimester. Overall, 7 pregnant women with confirmed Zika virus infections reported fever during pregnancy. Whether that affected their pregnancy outcomes is unknown.

The report in PLOS Neglected Tropical Diseases concerns a 20-year-old pregnant woman from Salvador, Brazil who had no symptoms of Zika virus but whose 18-week ultrasound showed intrauterine growth restriction. Subsequent second- and third-trimester ultrasounds showed severe microcephaly, hydranencephaly, intracranial calcifications, and destructive lesions of the posterior fossa as well as hydrothorax, ascites, and subcutaneous edema. At 32 weeks, labor was induced due to fetal demise. Polymerase chain reaction testing for Zika virus was positive in extracts from the cerebral cortex, medulla oblongata and cerebrospinal and amniotic fluid.

The authors of the case report believe that it may indicate a link between Zika virus infection and hydrops fetalis and fetal demise as well as microcephaly, but the results cannot be extrapolated to come to conclusions about the overall risk. They theorize that the mother may have been exposed to Zika virus during the first trimester, resulting in an intrauterine infection that led to the fetal hydranencephaly and hydrops fetalis.

The CDC is establishing a new registry for US pregnant women with confirmed Zika virus infection and their infants. Health care providers are encouraged to discuss participation in the registry with pregnant patients who have the infection and can contact Dana Meaney-Delman at ZikaMCH@cdc.gov or 770-488-7100 with questions about it.

NEXT: Does vaginal delivery increase risk of incontinence?


Does vaginal delivery increase risk of incontinence?

A recent systematic review published in European Urology suggests that vaginal delivery doubles the risk of stress urinary incontinence (SUI) for mothers when compared to cesarean deliveries. The findings, the authors said, may help women and their physicians with decision-making about mode of delivery.

More: Vaginal delivery and the pelvic floor

The analysis performed by the Clinical Urology and Epidemiology (CLUE) Working Group was based on a search of Medline, Scopus, CINAHL, and any relevant major conference abstracts that had been published up to October 2014 for adjusted analyses or other randomized trial that addressed the link between delivery mode and SUI ≥1 year after delivery.

The investigators pooled estimates from 15 eligible estimates and found an increased risk of SUI after vaginal delivery versus cesarean delivery (adjusted odds ratio [aOR]: 1.85; 95% confidence interval [CI], 1.56–2.19; I2 = 57%; risk difference: 8.2%). A larger effect among younger women was demonstrated following metaregression (P = 0.005). Four of the included studies seemed to indicate no difference in the risk of SUI between spontaneous vaginal delivery and instrumental delivery (aOR: 1.11; 95% CI, 0.84–1.45; I2 = 50%). Eight studies suggested an elevated risk of urgency urinary incontinence (UUI) following a vaginal delivery versus a cesarean delivery (aOR: 1.30; 95% CI, 1.02–1.65; I2 = 37%; risk difference: 2.6%).

The researchers concluded that vaginal delivery was linked to an almost 2-fold increase in risk of SUI with an absolute increase of 8%, which was age-dependent, and an absolute increase in risk of UUI of roughly 3%.

NEXT: Impact of vaccination on HPV prevalence


Impact of vaccination on HPV prevalence

A study by researchers from the Centers for Disease Control and Prevention (CDC) provides the first national evidence that human papillomavirus (HPV) vaccination is having an impact on women in their 20s. Published in Pediatrics, the report shows that prevalence of HPV-6, -11, -16 and -18 in this population has decreased significantly since the availability of the quadrivalent vaccine. 

The authors analyzed prevalence of HPV DNA in cervicovaginal specimens taken from women aged 14 to 34 in the National Health and Nutrition Examination Survey (NHANES). They compared presence of the four strains of HPV DNA in the prevaccine era (2003 to 2006) versus the vaccine era (2009 to 2012). Prevalence among sexually active women aged 14 to 24 years was also analyzed according to vaccination history.

Between the 2 time periods, the prevalence of the HPV types found in the quadrivalent vaccine declined from 11.5% to 4.3% among women aged 14 to 19  (adjusted prevalence ratio [aPR] 0.36; 95% confidence interval [CI] 0.21–0.61) and from 18.5% to 12.1% among women aged 20 to 24 (aPR 0.66; 95% CI 0.47–0.93). No decrease in prevalence of the 4 HPV subtypes was seen in older women.

Next: HPV vaccine rates, race, and income

From 2009 to 2012, prevalence of the 4HPV subtypes was lower (2.1%) in women aged 14 to 24 who were vaccinated (≥1 dose) than in those who were unvaccinated 16.9% (aPR 0.11; 95% CI 0.05–0.24). No statistically significant changes in other HPV type categories indicating cross-protection were found.

The investigators concluded that within 6 years of HPV vaccine introduction, there was a 64% decrease in prevalence of HPV-6, -11, -16, and -18 among women aged 14 to 19 and a 34% decrease among women aged 20 to 24.  “The decline in vaccine type prevalence after introduction of HPV vaccination,” the authors said, “is greater than expected based on current 3-dose coverage.”