Ebola Survival Rate Appears to be Higher in the West

Oct. 7, 2014

The Case Fatality Rate of Ebola (see West African Ebola - What is the true Case Fatality Rate?) has been estimated by the WHO at around 60% during this West African outbreak. In previous outbreaks fatality rates as high as 90% had been observed. According to the medical experts there is no treatment for the disease and all they can do is treat symptoms of the disease as the virus multiplies wildly within its host. The only potential control on this deadly viral multiplication is the body's own Ebola-activated immune response. Those patients who survive do so because their immune system is able to fight off the virus, rather than because of any specific medication they are given. This was the conventional wisdom, at least at the start of this outbreak.

However the scanty data available from Ebola treatment in the West during this outbreak appears to suggest at a minimum that immune systems do much better in Western hospitals than in their Mano River Union counterparts. A clear majority of the Ebola-infected in this outbreak who have been transferred to treatment centers in the West have been able to survive their infection.

U.S. health workers  Kent Brantley and Nancy Writebol contracted  Ebola in Liberia in July. They were repatriated to the  U.S. and have since recovered. Dr Rick Sacra, working for the WHO contracted Ebola in Liberia, was repatriated to the U.S. and was declared Ebola-free on Sept. 25 by the Nebraska Medical Center. Liberian  Eric Duncan, who travelled to the U.S. after contracting Ebola in his native land is currently fighting for his life in a Texas hospital. A fifth Ebola patient, a cameraman working for the US TV company NBC has just been flown to the US for treatment. Kent Brantley and Nancy Writebol were given the experimental drug Zmapp; supplies of this have now been exhausted. Rick Sacra was reportedly given blood donated by the first US Ebola survivor, Brantley, which would have contained antibodies to the virus.

British nurse William Pooley was flown home in August from Sierra Leone, where he had contracted Ebola. He has recovered after being treated with Zmapp.

A Senegalese man working for the WHO contracted Ebola in Sierra Leone in August and was sent to the University Medical Center, Hamburg, for treatment. He has since recovered. A second Ebola patient is now being treated in Frankfurt.

A French volunteer nurse for MSF in Liberia contracted Ebola and was evacuated to a hospital near Paris. She has recovered and has left the hospital, the French health ministry said in a statement. She was given the experimental drug, Avigan (also called Favipiravir), an anti-influenza drug manufactured by the Japanese company Fujifilm. There are reports that France and Guinea are now considering clinical trials of this drug, which is reportedly also being given to the second Ebola patient in Germany.

In these four countries, all six patients whose outcomes have been determined have survived. Among Western countries, however, Spain has not been as effective in treating Ebola. Miguel Pajares, 75, died in August in Spain after contracting the virus in Liberia. He was reportedly also treated with Zmapp. Manuel Garcia Viejo, 69, died in the hospital Carlos III de Madrid on 25 September after catching Ebola in Sierra Leone.

So, from Ebola patients in the West whose outcomes are known, the Case Fatality Rate, CFR, appears to be 2/8 or 25%. The survival rate is 75%.

Closer to home, during the Nigerian outbreak, which appears thankfully to have been brought under control, the CFR, at 40% was noticeably lower than it has been in Sierra Leone, Guinea and Liberia.

How are these countries managing to save more Ebola patients than we do here in the Mano River subregion? Have the experimental drugs played a role? Could hospital procedures and techniques play an important and, as yet, little understood role in the survival of Ebola-infected? In this regard, a look at Case Fatality Rates at different Ebola treatment facilities should provide important clues. When one looks at the CFRs of Ebola patients at the Kenema treatment center and at the MSF facilities (
West African Ebola - What is the true Case Fatality Rate?) one sees figures that are substantially different. These particular facilities, operating in the same region, have treated hundreds of patients drawn from the same region and a closer convergence of CFRs would be expected from such a large sample. These sorts of differences should be the subject of further, detailed study and would perhaps provide significant clues as to the most efficacious treatment for Ebola.