EXECUTIVE SUMMARY

Clinicians Are Urged To Maintain Vigilance Regarding The Zika Virus In Women Of Reproductive Age. Areas With Documented Local Transmission Of Zika, Such As Southern Florida, Parts Of South Texas, And Puerto Rico, Have Seen A 21% Jump In Births With Outcomes Most Strongly Linked To Zika Virus Infection.

  • Researchers at the Centers for Disease Control and Prevention examined about 1 million births during 2016 in 15 U.S. states and territories, including portions of Florida, Georgia, North Carolina, and Texas, as well as Hawaii, Iowa, Illinois, Massachusetts, New Jersey, Puerto Rico, Rhode Island, South Carolina, Utah, Vermont, and New York (excluding New York City).
  • Their analysis indicates that about three out of every 1,000 babies in the focus areas had a birth defect possibly associated with Zika virus infection in the mother.

Clinicians are urged to maintain vigilance regarding the Zika virus in women of reproductive age. Areas with documented local transmission of Zika, such as southern Florida, parts of south Texas, and Puerto Rico, have seen a 21% jump in births with outcomes most strongly linked to Zika virus infection.1

Researchers at the Centers for Disease Control and Prevention (CDC) examined about 1 million births during 2016 in 15 U.S. states and territories, including portions of Florida, Georgia, North Carolina, and Texas, as well as Hawaii, Iowa, Illinois, Massachusetts, New Jersey, Puerto Rico, Rhode Island, South Carolina, Utah, Vermont, and New York (excluding New York City).

Their analysis indicates that about three out of every 1,000 babies in the focus areas exhibited a birth defect that possibly was associated with Zika virus infection in the mother. About 50% of the infants were born with brain abnormalities and/or microcephaly, while 22% exhibited nervous system damage, including joint problems and deafness, without brain or eye abnormalities. One-fifth had neural tube defects and other early brain abnormalities, while 9% had eye abnormalities without brain abnormalities. Another increase in birth defects possibly related to Zika could occur when 2017 data are analyzed, since many pregnant women exposed to the Zika virus in late 2016 subsequently delivered in 2017, researchers surmise.1

The CDC analysis notes that for the infants who had birth defects linked to Zika virus, the majority of the mothers did not exhibit laboratory evidence of Zika virus infection because they were not tested, they were not tested at the right time, or they were not exposed to Zika virus.

To track birth defects that might be associated with the virus, the CDC uses two systems. The U.S. Zika Pregnancy and Infant Registry tracks pregnancies with laboratory evidence of Zika virus infection, while the Zika Birth Defects Surveillance system records birth defects possibly associated with virus infection, regardless of exposure or laboratory testing.

“Our pregnancy and birth defects surveillance networks are a collaborative effort with state, local, and territorial health departments and are essential to protect mothers and babies affected by Zika virus,” says Margaret Honein, PhD, MPH, acting director of the Division of Congenital and Developmental Disorders within the CDC’s National Center on Birth Defects and Developmental Disabilities. “These networks can also be used as models to help track other known and emerging health threats for mothers and babies.”

Drug May Find New Purpose

Researchers at University of California San Diego School of Medicine, working in conjunction with other international scientists, have published findings that suggest that an antiviral drug, sofosbuvir, currently used to treat and cure hepatitis C infections, may be repurposed as a potential treatment for adults, including pregnant women, infected with Zika.2

While much work has been done in addressing the Zika health threat, a large portion has been dedicated to developing a vaccine, notes the paper’s senior author, Alysson Muotri, PhD, professor in the UC San Diego School of Medicine departments of pediatrics and cellular and molecular medicine. (Results from two Phase I clinical trials now suggest that an experimental Zika vaccine developed by scientists at the National Institute of Allergy and Infectious Diseases is safe and induces an immune response in healthy adults; see the March 2018 Contraceptive Technology Update article, “Zika Remains on Research, Public Health Radar,” available at: http://bit.ly/2EZwVii.)

“But there is also a great need to develop clinical strategies to treat Zika-infected individuals, including pregnant women for whom prevention of infection is no longer an option,” said Muotri, who also serves as director of the school’s stem cell program. “They represent the greatest health crisis because a Zika infection during the first trimester confers the greatest risk of congenital microcephaly.”

Both hepatitis C and Zika are part of the same family of viruses and have structural similarities, the scientists note. By using human neural progenitor cells, which generate neurons and other types of brain cells, researchers found that drug exposure rescued Zika-infected cells and restored the gene expression linked to their antiviral response. Researchers then followed up by studying an immunodeficient mouse model infected by Zika. Their analysis suggests that intravenous injections of sofosbuvir significantly reduced the viral loads in blood serum of those who received the injections compared to those in a placebo group. Also, fetuses of pregnant mice infected with Zika did not show detectable Zika virus amplification in the drug-treated group.2

While findings are preliminary, Muotri says they demonstrate the potential for repurposing a drug that is already in wide clinical use for a similar viral infection.

“Until there is approval of a Zika vaccine, we think this is an approach that needs to be pursued wholeheartedly,” Muotri said in a press statement.

REFERENCES

  1. Fitzgerald B, Boyle C, Honein MA. Birth defects potentially related to Zika virus infection during pregnancy in the United States. JAMA 2018; doi: 10.1001/jama.2018.0126.
  2. Mesci P, Macia A, Moore SM, et al. Blocking Zika virus vertical transmission. Sci Rep 2018;8:1218.