Medecins Sans Frontiers "wasted time" by waiting too long to call for vaccines to fight an unprecedented outbreak of Ebola in West Africa, a veteran of the medical charity told Reuters.

The group's response to the epidemic which has so far killed more than 5,000 people has been widely praised by governments and the World Health Organization. While Western donors dithered and other aid groups pulled out, MSF deployed hundreds to the Ebola "hot zones" and treated more than 3,000 patients.

But the emergency group relied too much on strategies it developed during smaller previous eruptions of the virus, leading it to make mistakes as this year's rampant multi-country epidemic pushed it to its limits, said Jean-Herve Bradol, a member of MSF's internal think-tank.

"Our response was too orientated toward the management of previous outbreaks," Bradol, of the Paris-based Centre For Reflection on Humanitarian Action (CRASH), told Reuters, adding that MSF's public appeal for vaccine development in September came months too late.

"We wasted time before speaking about a vaccine and treatments... It's very hard to imagine controlling this epidemic now without a vaccine."

MSF, known also as Doctors Without Borders, is the only organization to have worked extensively with Ebola in the last 20 years. When the outbreak, first identified in March, started to spread, the group focused on established protocols of isolating patients and tracing their contacts.

At the same time, the group - treating patients at its six centers in Guinea, neighboring Liberia and Sierra Leone - criticized the slowness of the international response and clashed publicly with the Guinean government and the World Health Organization (WHO), which accused it of alarmism.

Since then the WHO has been widely criticized for its slow response to the epidemic and its early reassurances, despite warnings from MSF. The United Nations health agency has said it will publish a full review of its handling of the epidemic once it is under control.

Several companies are now accelerating vaccine trials. Two leading candidates, made by GlaxoSmithKline and NewLinkGenetics, have already started trials in Africa and Europe.

Separately, MSF said on Thursday that clinical trials of three potential new drugs would begin in December in Guinea and Liberia at medical centers it runs.

The West Africa Ebola epidemic has now infected more than 13,000 people.

ETHICAL TESTS

MSF was founded in 1971 by a group of French doctors and journalists outraged by the aid community's silence at Nigeria's blockade and starvation of separatist Biafra.

It prides itself on its speed and independence: with 90 percent of its $1.3 billion global budget funded by a legion of small individual donors MSF does not have to seek permission from any single major backer before acting.

The group has made 'bearing witness' a key part of its remit, from criticism of the military junta during the 1985 Ethiopian famine to calls for armed intervention to halt the Rwandan genocide in 1994.

That same attitude extends to self-criticism, said Bradol, noting that the remit of CRASH is to look at what MSF could have done better itself.

The current Ebola outbreak has brought ethical challenges for the group. When Sierra Leone’s foremost Ebola specialist, Dr. Sheik Umar Khan, lay dying in July, MSF doctors decided after fraught discussions not to treat him with an experimental drug, arguing its effects were unknown and supplies were scarce so it would be unfair to give him privileged care.

But when international healthcare workers fell ill - including two European members of MSF's staff - they were evacuated and given such treatments.

Such incidents sparked debate within MSF over why experimental treatments were not being offered to patients and its local staff, an unprecedented 15 of whom have died.

“The CRASH said...if you argue the drugs are not safe because they are experimental but you give them to the expatriates, that makes no sense," Bradol said.

FROM ALOOF TO INNOVATIVE

MSF staff complained at the start of the outbreak that other aid organizations failed to help treat Ebola. But the other aid groups complained that MSF refused to water down its rigorous safety protocols by training others.

Since then MSF has shared its blueprint for treatment centers and is training non-MSF workers in its center in Brussels. It also allowed staff from other NGOs to shadow its workers and use its logistics infrastructure.

Henry Gray, an operations coordinator for MSF-Brussels who worked for two months in Liberia and Sierra Leone, says the outbreak has also forced the group to innovate, developing watertight body bags to stop leakage of infected bodily fluids and climate controlled tents to allow doctors to work longer wearing heavy protective suits.

MSF has deployed more than 700 foreign staff in total to fight Ebola, rotating people through on six week stints. With the operation run at a cost of $50 million MSF staff are paid just $2,800 for a country manager.

"Nobody does this for the money," said Dr. Darin Portnoy, a long-time MSF volunteer from New York working at an MSF treatment center in Monrovia.