Challenges hobble U.S. public health response to Zika virus
The United States appears ill-prepared to deal with a Zika virus outbreak although the nation’s federal public health agencies have learned valuable information during the last few years about the disease, the U.S. Government Accountability Office (GAO) says in a new report released on Tuesday to coincide with a related House subcommittee hearing.
“Emerging infectious diseases present unique challenges to public health systems here and around the world,” said U.S. Rep. Tim Murphy (R-PA), chairman of the House Energy and Commerce Committee’s oversight and investigations subcommittee. “Despite the efforts, the unknowns about this disease still outweigh the knowns.”
Experts from several federal public health agencies testified during Tuesday’s hearing to fill in the representatives on whatever wasn’t learned from last year’s hearing on the same topic.
In fact, GAO’s report, “Emerging Infectious Diseases: Actions Needed to Address the Challenges of Responding to Zika Virus Disease Outbreaks,” expands upon what GAO initially determined about the response by federal agencies to the 2015-16 Zika virus outbreak that spread from Brazil. Previously confined to Africa and Asia, the outbreak marked the first time Zika had reached the Americas via the bites of female Aedes aegypti mosquitoes. Over two years, Zika spread to 61 countries.
What the Centers for Disease Control and Prevention (CDC) now know since that outbreak is that “a causal link” exists between Zika virus infection during pregnancy and microcephaly; Zika can be spread by vector bites and it can be sexually transmitted; and Zika can cause a form of paralysis known as Guillain-Barre syndrome.
Nevertheless, many mysteries remain. As the summer mosquito season begins, Murphy said, it’s time to reexamine the facts and “figure out what challenges our federal agencies continue to face.”
GAO says in its latest report that the U.S. public health agencies involved in responding to the 2015-16 outbreak used a reactive approach that had varied results.
“Once again, GAO has shown that we were not fully prepared at the outset of the outbreak,” Murphy said.
Indeed, a proactive approach would work much better, said Dr. Lyle Petersen, director of the Division of Vector-Borne Diseases at the CDC’s National Center for Emerging and Zoonotic Infectious Diseases.
“We do feel that we need to prepare and respond to the unexpected. A more proactive framework is what we should be doing,” said Petersen, who served as the CDC’s incident manager for the Zika response for most of 2016.
Figuring it out
Timothy Persons, GAO’s chief scientist, testified that the scientific and public health communities have learned a lot about the Zika virus over the past year, though the GAO report identifies “many areas where unknowns remain,” including:
– The total number of infections in the United States;
– The biological mechanisms, risks, reasons for geographic differences and full spectrum of outcomes associated with mother-to-child transmission;
– The risk of transmission from different bodily fluids and routes, including maternal-fetal transmission;
– The role of prior Zika virus infections or exposure to other related arboviruses; and
– The full spectrum of short-term and long-term outcomes of Zika virus infection, with or without clinical symptoms.
Additionally, GAO reports that “based on the totality of evidence from epidemiological studies, scientific consensus is now that Zika virus causes microcephaly, brain abnormalities and other birth defects” — findings that are both “emotionally difficult and highly expensive,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID). Microcephaly is a birth defect characterized by an abnormally small head resulting from an underdeveloped and/or damaged brain.
Fauci explained that Zika, a flavivirus, typically gets spread rapidly to new locations by large numbers of mosquitoes or ticks called vectors.
While infections caused by Zika virus are usually asymptomatic — with roughly 20 percent of infected individuals experiencing mild symptoms such as fever, rash, muscle and joint pain, and conjunctivitis — “of most concern, the recent outbreaks of Zika virus disease have coincided with a marked increase in the number of infants born with microcephaly,” Fauci said, particularly in Puerto Rico.
Fauci said that there aren’t any federally licensed vaccines or specific therapeutics currently available to prevent or treat Zika. However, he testified that NIAID, the lead institute at the National Institutes of Health (NIH) for conducting and supporting research on emerging and re-emerging infectious diseases that pose public health threats, is developing and investigating multiple Zika vaccine candidates, including vaccines based on technologies that have shown promise against other flaviviruses.
“A safe and effective Zika vaccine would be an invaluable tool to help stop the spread of infection and prevent future outbreaks,” Fauci told the congressmen.
Additionally, challenges exist around the development and use of diagnostic tools. The witnesses said that improved diagnostic tests are needed because a Zika virus infection is difficult to diagnose and distinguish clinically from other mosquito-borne infections, such as dengue, West Nile and chikungunya.
Lacking a “clear and transparent process for distributing CDC-developed diagnostic tests to manufacturers, the agency may not be able to develop the capacity of the commercial sector to be able to meet the needs during an outbreak,” Persons said.
Among GAO recommendations were that the Food and Drug Administration consolidate information from diagnostic test labels and require manufacturers to list the identity of comparator assays on the labels. GAO also recommends that the CDC provide detailed collection records and mosquito distribution maps, for example, and establish a transparent process to provide CDC diagnostic tests to manufacturers in the final stages of authorization.
It’s not over
Summer’s almost here and the time is ripe for vectors to strike. Petersen said, “Alarmingly, mosquito-borne diseases appear to be accelerating.”
When asked why, Petersen said the major causes are major world population growth, as well as increases in travel and freight that are rapidly transporting viruses to many places around the world.
Fauci said the nation won’t ever be able to prevent an outbreak of Zika. “The trick is to prevent it from becoming an epidemic,” he said.
Meeting these challenges requires funding, witnesses said, and the Democrats took the bait – and the opportunity – to slam President Donald Trump’s proposed FY 2018 federal budget, which was released Monday night by the White House.
The proposal calls for hefty funding cuts to the U.S. Health and Human Services Department, including roughly $800 billion in Medicaid cuts over 10 years, a move that Rep. Frank Pallone (D-NJ) said would “endanger our ability to manage public health emergencies like Zika.”
Rep. Janice Schakowsky (D-IL) said Trump’s proposed budget, coupled with the recent House repeal bill of Obamacare, would make it “nearly impossible for states to expand services during a public health emergency.”
“Medicaid plays an important role in responding to public health emergencies. It’s important to remember that,” Schakowsky said.
Rep. Susan Brooks (R-IN) said the Zika issue isn’t going away. “We must … keep our citizens safe and we will continue to work with you to ensure this happens,” she told the witnesses.