The quest for an Ebola treatment is picking up speed. Federal officials have unveiled a plan to test multiple drugs at once, in an umbrella study with a single comparison group to give fast answers on what works.

"This is novel for us" and is an approach pioneered by cancer researchers, said Dr. Luciana Borio, head of the U.S. Food and Drug Administration's Ebola response. "We need to learn what helps and what hurts" and speed treatments to patients, she said.

She outlined the plan Wednesday at an American Society of Tropical Medicine and Hygiene conference in New Orleans. Thousands of scientists have crowded into day and late-night sessions on Ebola, which has killed 5,000 West Africans this year.

There is no treatment for Ebola, but several experimental ones such as ZMapp have been tried on a few patients, and scientists are eyeing some others that were developed for different conditions but may also fight Ebola.

"There's this tremendous urge to want to give people these experimental therapies" but it's crucial to make sure they don't do harm, said the FDA's Dr. Edward Cox.

Everyone in the umbrella study would get supportive care, such as intravenous fluids, then be assigned to receive one of several drugs or be in a comparison group. That's needed because without one, there's no way to know if any problems or deaths are from the drug or the disease, Cox said.

Instead of waiting until a certain number of patients are treated to look at results, as is usually done, researchers will monitor results as they come in, pairing each person on a drug with someone from the comparison group to see if a pattern can be detected.

The National Institutes of Health developed this "learn as you go" plan "to allow a winner to be declared very early," Cox said.

He said the FDA could not name the drugs being considered, but said a meeting next week with various companies should crystallize the plans.

Ten potential vaccines have been developed, and two should enter mid- to late-stage testing in December or January, Dr. Cathy Roth of the World Health Organization told the conference via Skype from Geneva. GlaxoSmithKline's is one of them, and it's too soon to say when it could be ready for wide use or what it would cost, said the company's Dr. W. Ripley Ballou.

Poor countries "can't be expected to pay for it," so groups that have given aid in the past likely will be asked to do that, he said.

At least 30 scientists were barred from the conference because Louisiana state officials told attendees to stay away if they had traveled to certain West African countries or had contact with an Ebola patient in the last 21 days, Ebola's maximum incubation period. One was Dr. Amanda Tiffany of Doctors Without Borders, who was to have given a talk on how to limit the spread of Ebola, based on her work on some of the very first cases in Guinea.

"The stigma American and other colleagues are now facing is great," she said in a statement read by a colleague. "We need information disseminated through the media based on science and medicine and not on fear."

Dr. Daniel Bausch, a Tulane University doctor who has worked on the outbreak and advised the government on policy, said travel bans and quarantines were hurting the Ebola response.

The phrase "abundance of caution" is code for doing something based on fear rather than science, he said. "I don't think it calms people's fears, I think it enhances people's fears."

Ebola is setting back even the crude health care available in West Africa. In Sierra Leone, there now are no doctors willing to do Caesarean sections on pregnant women — whether they are known to have Ebola or not — because of the fear of exposure to so much blood, said Dr. Lina Moses, another Tulane researcher who works in that country.

"Maternal health is a serious issue right now," she said. "We're expecting maternal mortality to skyrocket."

A study published online by the New England Journal of Medicine confirmed a previous one that suggested age plays a key role in surviving Ebola. Patients over 40 were nearly four times more likely to die than younger ones were, a study in Guinea led by Dr. Robert Fowler at the University of Toronto found. Thomas Eric Duncan, the Liberian man who died at a Dallas hospital where he sought treatment, was 42.

New cases in some parts of Liberia are falling, but doctors fear it might be that fewer people are seeking treatment or staying away out of anger over seeing loved ones' corpses burned instead of the traditional funeral practices that can spread the virus, said Dr. Armand Sprecher, another Doctors Without Borders physician.

"I would really like to believe that things are slowing down there but I'm not going to get too optimistic yet," he said.

Having a treatment to offer could help doctors trace contacts of patients to limit the disease's spread. People "may be more willing to open the door" and answer questions if there is a drug that can help, Sprecher said.