Congress is preparing to build on a law aimed at preventing and responding to pandemics just as the flu season is swelling in the U.S. and ways to address it are falling short.

The law, the Pandemic and All Hazards Preparedness Act, or PAHPA, is up for its third reauthorization in the fall. It originally passed in 2006, soon after Hurricane Katrina destroyed the Gulf Coast and a strain of bird flu was spreading across Europe and Asia. The law aimed to better organize the ways that federal, state, and local departments respond to outbreaks and disasters, including by working with healthcare facilities, encouraging vaccine development, and boosting the number of healthcare workers.

It is aimed not only at addressing infectious diseases, but also natural disasters such as hurricanes and mudslides, as well as attacks such as mass shootings, terrorist strikes, or the threat of a biochemical weapon that would spread a deadly virus. Some of the original guidelines in the law were created under the Public Health Service Act, which were built upon in 2001 following the Sept. 11 terrorist attacks on the World Trade Center and the anthrax attacks in the mail.

Senators will spend the coming months looking for ways to make the law better, and will consider whether the amount and the way they deliver funding for these efforts should change. Over time, the appropriation for the programs created by the law have dwindled, and in recent years, political battles have gotten in the way of channelling funding quickly to various outbreaks.

“I think everything is on the table when you look at the reauthorization of a program like this,” Sen. Richard Burr, R-N.C., the author of the bill, told the Washington Examiner.

“I think that we have a relationship between state public health and federal entities like the Centers for Disease Control and Prevention and Health and Human Services in a way that didn’t exist prior to this, but what we’ve got to do is we’ve got to build on that to make the fabric even stronger."

In January, Burr led two hearings in the the Senate Health, Education, Labor and Pensions Committee to discuss the bill with experts from the medical field and from various health agencies. Sen. Lamar Alexander, chairman of the HELP committee, said in one of the hearings that the plan was to write legislation revisiting the act, mark it up in committee this spring, and then present it to the full Senate, where he hoped it would receive bipartisan support. The bill's provisions expire in September.

As the legislation is being considered, the country is facing public health crises on several fronts. CDC officials say this year's flu season is the worst the country has faced since 2009 and has estimated that the vaccine will be effective only 30 percent of the time.

Health and emergency officials are still trying to rebuild Puerto Rico following hurricane destruction that has left residents without electricity and clean drinking water for months. The hurricane also badly damaged Puerto Rico's manufacturing plants that produce medical supplies, causing a shortage of IV fluids just as the continental U.S. entered its flu season.

Overseas, China is being struck by a deadly strain of bird flu, and global health officials fear the spread of a deadly virus in East Africa known as Marburg, whose symptoms are similar to Ebola.

Officials who spoke during hearings about emergency preparations made logistical recommendations for the law, such as building more stockpiles of vaccines and continuing to invest in the development of a universal flu vaccine that would need to be administered only once and would protect against a range of flu strains.

Dr. Tom Inglesby, director for the Center for Health Security at the Johns Hopkins Bloomberg School of Public Health, said that since the passage of the earlier versions of the law, hospital responses to smaller events have improved, such as responses to mass shootings. He cautioned, however, that "the nation is not ready to provide medical care in large catastrophes or big epidemics of contagious disease." He cited the example of how hospitals had trouble managing Ebola patients.

Burr noted similar lessons from the experience with Ebola preparation, saying a vaccine should have been available.

“We worked on it a number of years ago, but it was shelved because we didn’t believe we needed it," he said. "All of a sudden, we needed it, and we scrambled to find a way to deal with it. We shouldn’t scramble in the future; we should have the capacity out there, because we don’t know whether it will be Ebola or another infectious disease, or something that is intentionally launched on us. Our capacity to deal with it ought to be in place."

Senators and witnesses at the hearings also acknowledged that addressing pandemics in recent years has been stopped not only by a lack of planning but also by political battles.

"We had lengthy delays both in the Ebola response and the Zika response before funding became available. I think that hindered what we were able to accomplish," said Dr. Stephen Redd, director of the CDC's Office of Public Health Preparedness and Response.

Federal funding to stave off the lead water crisis in Flint, Mich., was delayed for nearly a year. Funding for the Zika virus came more than seven months after former President Barack Obama's request, as the issue became weighed down by a battle over contraception and abortion in which some lawmakers demanded no money be allowed to go to Planned Parenthood. The virus is primarily spread through mosquitoes but also through sex, and when a pregnant women is infected, she risks giving birth to babies born with abnormally small heads and brain damage.

As officials waited for an appropriation from Congress, they pulled $500 million in funding from Ebola, which had spread rapidly across East Africa the year before.

One proposal to hasten the response is the creation of a Public Health Emergency Contingency Fund, which would set aside money that officials could quickly access, rather than shift dollars from other programs or wait for an appropriation from Congress. The possibility of creating such a fund was raised several times during the HELP hearings.

There is some support among politicians. President Trump's 2017 budget proposal advocated for its creation, and a standalone bill to create the fund was introduced by a bipartisan group of senators, led by Sen. Bill Cassidy, R-La. Cassidy's office said the PAHPA bill is one possible vehicle to advance his proposal.

Following the hearings, Sen. Johnny Isakson, R-Ga., told the Washington Examiner that a public health emergency fund could be considered to improve on the law.

“I think we need to find a way to get a continuous flow of funding for the agenda,” he said. “It’s all about preparedness; it takes money to prepare.” He cited “working on some degree of preparedness and a predictable funding stream of money” as two areas to address.

Two of the programs that are supported under PAHPA have seen a depletion in funds because of lower appropriations from Congress over the years. The Hospital Preparedness budget is down from $514 million during its 2003 inception to less than half that by 2017, at $254 million. The Public Health Emergency Preparedness Program is down to $667 million from $940 million in 2002.

The decline in funding has occurred even as medical experts say the threat of a pandemic hasn't lessened.

"There should be more funding for public health preparedness for emergencies, not less," Inglesby said.

Sen. Bob Casey, D-Pa., pointed to the decline in funding as an area of concern.

"I do think there is one glaring weakness where we are now compared to where we were 15 years ago: the funding gap ... hundreds of millions of dollars was cut over time that in no way helped the country," he said.

"How the hell does the country benefit when we cut those two programs? The funding appropriation issue is big, but I think we are still wrestling with where the policy gaps are."

Asked whether PAHPA, which has previously received bipartisan support, could become gridlocked in a political battle, Casey replied: "Everything is difficult here. This is of such urgency that Richard [Burr] and I have kept it on a bipartisan plan, and I think a lot of other people have as well. So, we'll do our best to keep it on that foundation."