The U.S. government's top infectious disease expert said he was confident in the National Institutes of Health's experimental Zika vaccine and has launched it into the next phase of human testing — a significant step for the product.
Initial findings of the phase 1 trial of the DNA-based vaccine, which was discovered and developed by U.S. government scientists, indicated the product was safe and able to induce a neutralizing antibody response against Zika, Anthony Fauci, director of the NIH's National Institute of Allergy and Infectious Diseases, told reporters March 31.
Fauci said the follow-up $100 million two-part phase 2 trial of nearly 2,500 participants aims to gain more safety and immune response data to determine if the vaccine protects against the virus, which is spread mainly by the Aedes aegypti mosquito.
Fauci acknowledged the NIH has yet to seal a deal with an industry partner to carry the vaccine into phase 3 development and to the marketplace.
But he said he was "actively negotiating" with a couple of biopharmaceutical firms to potentially conduct the phase 3 testing and commercialize the NIH vaccine. Fauci declined to identify those companies, but he said "it is almost certain" the NIH would have a partner by the time it starts phase 3.
He dismissed the notion interest in a Zika vaccine was waning.
"I'm totally intent on getting this vaccine to the point where it can be a usable vaccine," Fauci said.
A handful of biopharmaceutical companies are pursuing their own Zika vaccines, like Sanofi, GlaxoSmithKline PLC, Moderna Therapeutics and Inovio Pharmaceuticals, although using a different strategy than the NIH. Some of those products are partnered with the NIAID, the Department of Defense and the U.S. Biomedical Advanced Research and Development Authority.
Sanofi has teamed with the DOD's Walter Reed Army Institute of Research on its investigational purified inactivated virus vaccine, while GSK has partnered with the NIAID on the company's self-amplifying mRNA candidate.
The NIH DNA vaccine uses a strategy similar to what was employed for an experimental product developed by the agency to prevent the West Nile virus, which belongs to the same family of viruses as Zika, known as flavivirus. The West Nile virus vaccine candidate, however, stalled in development because of a lack of an industry partner.
The NIH's Zika vaccine was accelerated into human testing last summer in response to a 2015 outbreak that spread through much of South America, especially in Brazil, and then made its way to the U.S. and its territories last year.
Zika has minimal effects for most people, but has devastating consequences if pregnant women contract the disease, which can cause their fetuses to develop microcephaly, a rare neonatal malformation in which a baby's head is much smaller than normal, resulting in developmental and other disabilities.
There were more than 38,300 cases of Zika reported in U.S. territories, more than 3,300 of whom were pregnant women, the CDC said on March 30. The agency reported there were nearly 5,200 cases of the virus reported in the U.S. states and the District of Columbia, over 1,600 of whom were pregnant women.
The agency said there have been 54 babies born with Zika-related birth defects in the U.S.
The World Health Organization on Feb. 1, 2016, declared Zika a public health emergency of international concern because of the virus' "strongly suspected" link to microcephaly in Latin America.
That prompted President Barack Obama to request $1.9 billion in emergency funding for Zika, but the funds got caught last year in a political fight, forcing the NIH to borrow cash from other projects, including its effort to develop a universal flu vaccine and the ongoing Ebola response.
Congress finally came through with $1.1 billion for Zika on Sept. 28, 2016 — nearly nine months after Obama sought it.
Fauci said the funding for the phase 2 study already had been allotted to the NIH from that emergency fund, so he said he was not worried the trial's progress would be hampered in any way by President Donald Trump's proposal to cut $6 billion from the agency's fiscal-year 2018 budget and another $1.2 billion from the current year.