How the CDC issues Zika medical guidelines

As researchers learn more about the Zika virus every day, recommendations for healthcare providers must be constantly adapted.

Sonja RasmussenAlthough research is unfolding, much is still unknown about the Zika virus and complications it causes. Without established best practices, medical professionals turn to government agencies like the US Centers for Disease Control and Prevention (CDC) for guidance on how to treat and advise their patients. Sonja Rasmussen is Editor-in-Chief of the Morbidity and Mortality Weekly Report (MMWR), the CDC’s primary publishing platform for public health recommendations, and contributes to the agency’s Zika response as a member of its Pregnancy and Birth Defects Task Force. We asked her how she and her colleagues arrive at the recommendations they issue in this environment of medical uncertainty.

ResearchGate: How would you characterize the current state of Zika virus research?

Sonja Rasmussen: Although Zika virus is not new, its potential effects on pregnancy are something that hadn’t been previously recognized. That means we are quite literally learning more about Zika and what it means for pregnant women each and every day.

RG: How does the CDC approach medical guidelines when there are a lot of unknowns about the virus and its effects?

Rasmussen: Every new finding from a published study, each new data point, is collected as part of the US Zika Pregnancy Registry – all this information feeds into what we know about Zika and directs our public health action. We continually evaluate all of the available evidence and update our guidelines as new information becomes available.

RG: How does the CDC stay on top of rapidly emerging research results?

Rasmussen: CDC activated its Emergency Operations Center on January 22. This allows us to bring together scientists across CDC with the necessary expertise we need to respond to the Zika virus outbreak and protect pregnant women. CDC is collaborating with local, national, and international response partners to analyze, validate, and efficiently exchange information about the outbreak.

As part of the CDC Zika response, I am working on the Pregnancy and Birth Defects Task Force. Our task force is focused on learning more about Zika’s effects on pregnancy. We have a team of people reviewing and summarizing emerging research, responding to inquiries from health care providers and the general public, and applying what we learn to update our guidelines and recommendations.

RG: How do you balance quality control with the need to quickly adapt guidelines to the latest research?

Rasmussen: Because what we know about Zika is evolving so quickly, we see our guidance as living documents, allowing us to be flexible and make adjustments to integrate all that we’re learning. We strive to provide recommendations based on the current knowledge. Because the science is progressing rapidly, CDC will frequently update the guidance. While we strive to make our guidance based on the most current evidence, guidelines cannot always keep up with the rapid evolution of new data; therefore, patient management decisions should be based on clinical judgment and attention to individual patient circumstances.

RG: What is the most pressing research area related to the Zika virus?

Rasmussen: While we’ve learned a lot about Zika in a very short amount of time, many questions remain. We still don’t know the level of risk from a Zika infection during pregnancy; that is, if a woman is infected, how often will her fetus have problems. We also don’t know the full spectrum of potential health effects. Zika virus is linked to microcephaly, but what about other types of birth defects, other than those involving the brain? Does Zika cause problems with the brain that aren’t visible at birth, such as learning problems later in life? Are pregnancy losses seen in some women infected by Zika virus caused by the infection? Another key question is whether there are other factors that might affect the risk of Zika? Not all people with Zika virus get symptoms – are women who are symptomatic more likely to have babies with birth defects?

RG: Is there an example of Zika research results that surprised you and have caused the CDC to revise its guidelines?

Rasmussen: We did not expect that we would see this many sexually transmitted cases of Zika virus disease.  When sexual transmission in the current outbreak was first documented, we issued guidance on sexual transmission – indicating that men who live in or who have returned from an area with active Zika transmission use a condom if they have sex with a woman who is pregnant or abstain from sex for the remainder of the pregnancy.

RG: MMWR was where the first cases of the AIDS pandemic were reported. Has this historical context influenced the publications’ contemporary understanding of the role it plays in viral research and public health?

Rasmussen: The goal of the Morbidity and Mortality Weekly Report (MMWR) is to provide timely, reliable, authoritative, and useful public health information and recommendations. Similar to the early reports on AIDS, MMWR has responded quickly to the Zika virus epidemic by publishing important new research on Zika and updated clinical guidelines. MMWR has published major articles that have advanced our understanding of Zika, including a report that described clinical findings in 35 infants from Brazil with microcephaly and presumed Zika virus infection, published in January, and a report that demonstrated the detection of viral RNA and antigens in brain tissues from infants with microcephaly and placental tissues from early miscarriages, providing strong evidence for the linkage of Zika to these adverse pregnancy outcomes. In addition to this important research, MMWR has played an important role in publishing the latest guidelines for pregnant women, women of reproductive age, and infants, as well as guidelines to prevent sexual transmission of Zika virus. All of MMWR’s Zika reports are online.

ResearchGate has put together a collection of emerging Zika virus research, including scientific papers, interviews with researchers, and discussions among them. 

Featured image by James Gathany, Centers for Disease Control and Prevention.