July 15, 2016 10:07 AM EDT

Public health researchers say Congress’ failure Thursday to pass funding to fight the Zika virus will hurt efforts to fight it, including stalling research into a potential vaccine and how the virus causes birth defects.

Scientists had already warned that the $1 billion in proposed spending was coming too late. More than 1,300 people in the U.S. already have the virus. The disease is spreading rapidly in Puerto Rico, an American territory.

“Without a clear commitment from the federal government, private sector partners working on diagnostics and vaccines will choose not to proceed,” Marissa Padilla, a spokeswoman for the U.S. Dept. of Health and Human Services, told TIME. “Meanwhile, countless other efforts to combat Zika will be jeopardized.”

Read More: Zika Funding Bill Fails as Congress is Unable to Reach Compromise

The first human trials in the U.S. of a Zika vaccine were approved about a month ago. Without this federal funding, Padilla said those trials will be put on hold. The government will also suspend research into the link between Zika in pregnant mothers and microcephaly, a birth defect that shrinks a baby’s head. Scientists know the Zika virus survives longer in pregnant women than in other people. But there are still many unknowns about Zika, microcephaly and how to prevent it. This permanent damage has already affected at least nine children in the U.S. In Central and South America, more than 1.5 million people have contracted Zika.

The vaccine is relevant beyond this year’s remaining months of warm weather. A study published this week said the outbreak could continue for three years, ramping up and down as mosquitoes swarm in warmer climates each summer.

In 2014, as Ebola ravaged West Africa and a fear grew the deadly disease would spread in the U.S., Congress allocated $5.4 billion to fight it. Much of that money went unspent. Some House Republicans believe the administration should spend that remaining money to fight Zika. But federal officials say it is not that simple.

Some Ebola money has been redirected, Padilla told TIME, but she added the funds cannot simply be diverted to Zika. Ebola money has been used to ship Zika-free blood and thousands of prevention kits to Puerto Rico. On July 1, $25 million was granted to cities and states to develop preparedness plans to fight Zika. And $10 million will soon be spent to help states track the babies of mothers who had Zika during pregnancy.

Read More: Zika Funding May Already Be Too Late

While these monitoring and prevention efforts are useful, officials believe they will do little compared to the difference made by a vaccine or widespread prevention efforts. In Florida and Texas, where a certain kind of mosquito makes the states prime transmission spots for Zika, public health officials worry what the remaining seven weeks of summer will bring.

“We are disappointed,” Dr. Umair Shah, executive director of Harris County Public Health in Texas, told TIME on Thursday. Harris County is home to Houston and 4.3 million people. “It would be a lot better if we had those resources. I have to be honest, our team is stretched quite a bit.”

Contact us at letters@time.com.

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