The US Food and Drug Administration's (FDA) acting chief scientist told members of the House Energy and Commerce Committee on Wednesday that FDA is investigating all avenues to combat Zika, including a proposal to release genetically engineered mosquitoes in Florida.
Scientists expect that the virus, which has swept across Latin America and the Caribbean, will eventually reach US shores, especially in states like Texas and Florida that have experienced outbreaks of dengue virus in recent years.
In her testimony, FDA's Dr. Luciana Borio told Congress that she is "working closely" with other federal agencies, as well as with peers at other national regulatory authorities.
"Last month I had the privilege to travel to Brazil, my country of birth, with a small [Department of Health and Human Services] HHS delegation, to meet with the Brazilian Minister of Health and several of his senior officials. The engagement was extremely productive. In particular, FDA and ANVISA, Brazil's national regulatory agency, committed to working very closely and reach convergence in areas of vaccine development and diagnostic tests," Borio said.
Last week, FDA authorized the first diagnostic to detect Zika under its emergency use authorization pathway (EUA) after HHS Secretary Sylvia Burwell declared the virus poses a "significant potential" to cause a public health emergency.
US Centers for Disease Control and Prevention (CDC) Director Tom Frieden applauded FDA for its quick turnaround in authorizing the test and said CDC plans to start distributing the test to authorized labs in the next two weeks.
The test, known as the Zika Immunoglobulin M (IgM) Antibody Capture Enzyme-Linked Immunosorbent Assay, or Zika MAC-ELISA for short, was adapted to detect Zika by the CDC earlier this year. Because of the risk of cross reaction with other types of Flavivirus, such as dengue, positive or ambiguous results must be confirmed by a polymerase chain reaction (PCR) test.
When asked about the capacity of laboratories to perform the test, Frieden said, "We are concerned about the capacity," but added that his agency has been working around the clock to produce the two diagnostics. "For the PCR we've produced more than 370,000 of them, we think that's ample, for the [Zika] MAC-ELISA we're up around 100,000," he said.
Borio also told House representatives that FDA is working with "several" diagnostic companies and will coordinate with clinical labs seeking to develop their own tests.
"In recent weeks we have seen an increased interest by clinical laboratories to develop their own tests for Zika … to support these efforts, FDA developed simple templates that developers can submit … for expedited review … FDA is urging developers to work with us to ensure their tests meet the standards for accuracy and precision," she said, adding that the agency will "not hesitate to take appropriate action to prevent the use of tests that do not meet our standards."
Genetically Engineered Mosquitoes
In addition to other traditional methods of mosquito control, Borio said FDA is reviewing a proposal submitted by Oxitec to release its OX513A genetically modified Aedes aegypti in Key Haven, Florida.
The mosquito, which has been modified so that its offspring die before reaching maturity, is already approved in Brazil and has been tested in that country, as well as in the Cayman Islands, Panama and Malaysia.
If Oxitec's proposal is approved, it would mark the first time the genetically modified insect is released in the US. Before that can happen, Borio says FDA will release an environmental assessment and other findings for public comment.
"It's very important for us to go through the process and include the public comment … we need to give the public an opportunity to comment on the environmental assessment, given the significant attention that this novel technology has generated, especially in the communities where the proposed sites [are]," Borio said.
"We don't know where the public stands," she said.
While Borio said FDA has been expediting its review of Oxitec's genetically engineered mosquito, she said the agency would not be authorized to approve the genetically engineered mosquito for emergency use.
"Our EUA authority is currently limited to human products, not to animal products, and this technology is regulated under our animal drug regulation," she said.
When asked what Congress could do to help with response efforts, Anthony Fauci, director of the National Institute of Allergy and Infectious Disease (NIAID), quickly replied, "I think that we need some money."
Both Fauci and Frieden emphasized the need for supplemental funding from Congress.
"We can't let down our guard, supplemental funding is essential," Frieden said.
In order to fund the CDC's Zika efforts, Frieden said his agency was diverting resources from other infectious disease programs.
Last month, President Barack Obama called for $1.8 billion in funding for efforts to combat Zika in the US and abroad. Rep. Curt Clawson (R-FL) also has submitted a bill that would provide $200 million annually to fight Zika through 2020.