01:44 - Source: CNN
Why isn't Ebola containment working?

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NEW: NIH is testing Ebola vaccine, now has patient who was exposed to the virus

Patient is a U.S. doctor who volunteered in Ebola treatment center in Sierra Leone

The doctor is at the clinic for observation, research and will be in isolation

NIH says safety measures are in place to protect other patients and the public

(CNN) —  

An American doctor who was exposed to Ebola has arrived at the NIH Clinical Center in Bethesda, Maryland, the National Institutes of Health said Sunday.

The doctor was volunteering at an Ebola treatment unit in Sierra Leone and arrived from an “overseas location” according to the NIH.

No more details on the patient were made available, but the doctor will be there for observation and research purposes, officials said.

The NIH is currently testing an experimental Ebola vaccine on human volunteers that did extremely well in earlier trials with chimpanzees, doctors say.

The patient will be kept in isolation.

“Out of an abundance of caution, the patient has been admitted to the NIH Clinical Center’s special clinical studies unit that is specifically designed to provide high-level isolation capabilities and is staffed by infectious diseases and critical care specialists,” the NIH statement said. Safety measures are in place to protect other patients and the public.

The Ebola outbreak in West Africa is the worst on record, according to the World Health Organization. The number of deaths from Ebola now stands at 3,083 and the number of cases has reached 6,553, the WHO said in a statement. The figures are based on information provided on September 23 by health ministries in Guinea, Liberia and Sierra Leone, the countries most impacted by the Ebola outbreak.

CNN’s Miriam Falco contributed to this story