According to an Associated Press-GfK poll released Wednesday, Americans are worried about Ebola spreading here, and many say the government hasn't done enough to prevent that from happening. The poll found a surprising 9 out of 10 people think it's very necessary to tighten screening procedures.

Some would go even further: Three-quarters think it's definitely or probably necessary to prevent everyone traveling from places affected by Ebola from entering the US

On Wednesday, White House spokesman Josh Earnest said the president has been following advice from scientists that a travel ban could do more harm than good. Health officials fear travelers will just find alternate routes and spark harder-to-trace outbreaks.

Many health experts agree that a travel ban is a bad idea. But one faulted the CDC for being slow to institute the daily monitoring.

Monitoring can't stop Ebola from coming in, "but we'll have a better chance" to quickly identify and isolate cases, said Dr. Richard Wenzel, a Virginia Commonwealth University scientist who formerly led the International Society for Infectious Diseases

Such tracking measures might have made a difference in the case of Thomas Eric Duncan, the Liberian man who became the first person diagnosed with Ebola in the United States, Wenzel said. Duncan wasn't sick and passed the screening when he left Liberia. He didn't develop symptoms until after his arrival. He died Oct. 8.

Two nurses who took care of him at Texas Health Presbyterian Hospital were infected; both remain hospitalized. The family of one nurse, Amber Vinson, said Wednesday that tests show the Ebola virus can no longer be detected; the Atlanta hospital where she is being treated wouldn't release any information.

Maryland's health secretary said it will depend on individual circumstances how closely the state monitors people. Dr. Joshua Sharfstein said the approach will recognize "that some people who come from West Africa are at a higher risk than others." The CDC isn't mandating that everyone be watched the same way, he said.

Also on Wednesday, an American video journalist who has recovered from Ebola was being released from a Nebraska hospital. He caught it while working in Liberia.

"Today is a joyful day," Ashoka Mukpo said in a statement issued by the Nebraska Medical Center in Omaha. He arrived Oct. 6.

Meanwhile, President Barack Obama brought together top aides and his new Ebola coordinator Ron Klain. After their meeting, Obama gave assurances that hospitals across the country were becoming better prepared in the event they have to deal with cases of Ebola.