President Donald Trump has proposed $7 billion in spending cuts at the National Institutes of Health, but the agency's Zika vaccine effort won't be among them, at least not yet. NIH officials said Friday they had pushed their candidate into phase 2 testing with $100 million of earmarked funding.

NIH’s National Institute of Allergy and Infectious Diseases has started testing its Zika vaccine candidate in a multisite phase 2/2b trial, which aims to enroll at least 2,490 healthy volunteers in Central and South America as well as the U.S. The targeted countries include Puerto Rico, Brazil, Peru, Costa Rica, Panama, Mexico and the U.S., all of which have reported confirmed or potential active transmission of Zika.

NIAID director Anthony Fauci, M.D., said on a Friday conference call that $100 million has already been allocated to see this trial through, and thus the project will not be affected by Trump’s proposed cuts.

Fauci would not comment on future cuts and their potential effects on the Zika program, saying the federal budget is not settled yet. Zika vaccine development is "high priority" at the agency, he said, and NIAID could seek out a pharma partner to share the cost of phase 3.

In his budget blueprint laid out last month, Trump first proposed a $5.8 billion (20%) cut to NIH funding for the next fiscal year. The president immediately followed up with another proposal to ax $1.2 billion from 2017 spending.

The NIAID's Zika candidate uses the same platform as the agency's West Nile virus shot. It contains a small piece of DNA augmented with two proteins found in the Zika virus. Once injected, the proteins turn into noninfectious particles that resemble the virus itself—and trigger an immune response as the virus would.

For the first part of the phase 2/2b program, researchers will enlist 90 participants to further evaluate the vaccine’s safety and ability to stimulate an immune response, and to help determine an optimal dose. The participants will receive three shots, with one group receiving the standard 4 mg dose and the other an 8 mg dose, NIAID said.

The second portion of the study, which Fauci expects to begin this June, will test whether the vaccine can protect people against Zika when they’re naturally exposed to the virus. Healthy women of child-bearing age can participate in the trial, but no pregnant women will be included; Zika is known for its devastating link to microcephaly in infants.

NIAID expects initial results to be available at the end of this year and aims to wrap up in 2019. But Fauci said the timeline will depend on the number of people exposed to the virus. If too few are exposed to deliver an effectiveness signal, NIAID might expand the trial to as many as 5,000 participants.

The candidate, developed by scientists at NIAID’s Vaccine Research Center, was the second Zika shot to enter human testing. Its previous data showed a good safety profile and an antibody response against the virus.

Inovio, together with its partner, GeneOne Life Science, was the first to test a Zika vaccine in humans. Back in February, Inovio presented positive top-line results for its candidate GLS-5700, also a DNA-based shot.

Many other companies are also in the race, including Sanofi, Takeda, GlaxoSmithKline, Themis and GeoVax, all working with their own governmental or institutional partners such as Brazil’s Fiocruz, Walter Reed Army Institute of Research, the HHS’ Biomedical Advanced Research and Development Authority, and the CDC.

Last fall, the World Health Organization decided that Zika was no longer an international emergency, but declared the health community's fight against the virus still required "intense action."