After months of bickering, Congress agreed Wednesday to allocate $1.1 billion toward curbing the spread of the Zika virus, a primarily mosquito-borne disease that has raised public health alarms.

The package is part of a larger spending bill to keep the federal government running until Dec. 9. It comes as the virus — which can cause birth defects if contracted by pregnant women — is actively spreading in Florida. More than 3,000 cases have been reported in the continental United States, though most were contracted by people traveling abroad.

So what exactly has Congress done? And, from a public health standpoint, how much will it help? Here is a breakdown of what you need to know.

First Things First: A Reminder Of Why Zika Causes Concern

Zika is a virus that has been spreading globally since last year. It is transmitted by mosquitoes and also through sexual intercourse. The virus has already moved through African and Latin American countries. Currently, mosquitoes are carrying it in parts of Florida. Experts worry these mosquitoes will spread to other Gulf Coast states — such as Texas, Louisiana and Georgia, where hot, humid climates are particularly friendly to the insects.

For most of the population, Zika doesn’t appear to be a huge deal. About 80 percent of people who are infected don’t show symptoms at all. Those who do typically suffer a flu or maybe a bad rash.

But for pregnant women, it’s a different story. Zika can cause severe birth defects in children — including but not limited to microcephaly, which stunts brain development — and has been linked to other complications in pregnancy.

It’s unclear how often those complications result, though, and researchers are still investigating other possible consequences Zika might have in terms of fetal development and for both mother and child’s long-term health. So, long story short: The virus can be incredibly damaging. How often that’s true, though, remains unclear.

This $1.1 Billion — What Will It Actually Do?

The funding consists of two pots: one, totaling almost $935 million, for efforts curbing Zika’s spread at home; and another, for about $175 million, targeting it abroad.

Domestically, the money’s split among prevention, responding to the virus and developing treatment. So far, there’s no vaccine or cure for Zika. Congress has approved $152 million for the National Institute of Allergy and Infectious Diseases (NIAID), which is researching potential vaccines.

The Centers for Disease Control and Prevention gets $394 million, which the agency can use in areas affected by Zika. Another $387 million is for the U.S. Department of Health and Human Services’ public health emergency fund and will be used for activities like providing Zika testing and caring for people who have been affected by the virus.

That money will be essential in states and territories where Zika poses a threat, said Chris Gould, senior director for federal government relations at the Association of State and Territorial Health Officials. The CDC’s funds, for instance, could support programs that eliminate mosquitoes, monitor the virus and educate people at risk.

“This amount, even though it’s long overdue, still will certainly go a long way in terms of helping states get what they need,” Gould said.

On the foreign aid side, the money will go to the State Department to support activities such as evacuating eligible pregnant Americans from countries where Zika is spreading and helping hard-hit foreign nations address their own Zika issues.

How Does This Funding Amount Compare To What Public Health Experts Want?

This falls short of the $1.9 billion President Barack Obama originally sought. But it’s fairly similar to a package the Senate first floated in May. Here, the key difference is increased funding for domestic efforts, with less for the State Department’s international efforts.

How does this hold up, then? Public health advocates said more money, of course, would have been better but said this is a meaningful start.

In this measure, Congress provided less research funding than the NIAID requested — the agency would ideally get $40 million more, said director Anthony Fauci. That said, the funds should be enough to maintain “critical vaccine studies,” though the agency will have to trim other Zika work, he added, such as “more fundamental research” on the virus and its properties.

Also, the bill passed by the Senate in May snagged after the House of Representatives argued that Congress would somehow have to offset any new funding — repurposing dollars intended for use elsewhere, for instance — and pressed to include language barring Planned Parenthood affiliates in Puerto Rico from getting federal dollars.

Planned Parenthood isn’t mentioned in the final agreement. About $400 million of the new package comes from repurposed money, much of it originally meant for combating the Ebola virus and for implementing provisions of the 2010 federal health law.

Borrowing against Ebola funding is problematic, argued Lawrence Gostin, a professor at Georgetown University and faculty director of its O’Neill Institute for National and Global Health Law. “That money is needed to fulfill our promise to be vigilant about Ebola,” he said.

Congress Has Been Fighting About Zika For A Long Time. Has That Delay Had Any Consequences?

Yes. Mosquito season generally peaks in the summer, though it’s certainly longer in states like Florida and Texas. So for many at-risk states, it’s too late to do any real prevention work — at least this time around.

For instance, it’s possible that Zika is being actively spread in states other than Florida, said Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine. No one would know, he said, because there has not been enough money to support thorough surveillance.

“We will not know how well we’re doing until next April or May when we see if babies with microcephaly are being born,” he said. “We have to be on top of it — we have to hold our breaths until April or May.”

In the meantime, he added, while the funding may be too late to really make a difference this year, it could lay the groundwork to undermine future Zika threats.

So What’s Next? Is The Zika Problem Solved?

Probably not. While mosquitoes die down in the fall, experts say Zika will likely present a public health concern for the next few summers and that, in all likelihood, more money will be needed if Congress hopes to keep the virus at bay.

Right now, states should be able to appropriately respond to Zika with the funds Congress is allocating, Gould said, assuming the virus does not suddenly spread much more quickly than it has been so far. But there needs to be an understanding that “when this money runs out, Zika may not run out.”

“We’re not going to measure Zika in this one cycle,” Gould said. “We’re talking years.”