Experts convened by the World Health Organization (WHO) believe that blood products from Ebola survivors may offer early help in West Africa's Ebola epidemic, and limited doses of two candidate vaccines may be ready to use as early as November, depending on the outcome of safety studies, the WHO announced today.
"We agreed that whole blood and convalescent serum may be used to treat Ebola virus disease and that all efforts must be directed to help affected countries use them safely," Marie-Paule Kieny, PhD, the WHO's assistant director-general, told reporters in a press teleconference from Geneva.
She said safety studies of the two most advanced vaccine candidates are getting started in the United States now and will begin in Africa and Europe in mid-September. If the vaccines are found to be safe, some doses could available for use in healthcare workers (HCWs) in November.
Kieny noted that Canada plans to donate 800 doses of one vaccine, and said 10,000 doses of another vaccine may be available from GSK by the end of the year.
"There is a tide in the affairs of men, and that tide is now. We have to change the sense that there is no hope in the situation to a realistic hope," Kieny said at the briefing, which followed a 2-day conference of about 200 experts on the use of experimental drugs and vaccines to fight the expanding epidemic in West Africa.
As for experimental drugs under consideration, Kieny said it will likely be at least a few months before any can be used on a scale beyond small safety studies.
Ebola deaths top 2,000
Today's announcement coincided with more news on the expansion of the epidemic in Guinea, Liberia, and Sierra Leone. In its second situation report since the WHO's Ebola roadmap was unveiled, the agency said cases as of today have reached 3,944, with 2,097 deaths. Just yesterday the WHO put the numbers at 3,685 cases and 1,841 deaths, as of Aug 31.
The new report also says that Nigeria now has 23 cases and 8 deaths, while the count in Senegal remains at 1 nonfatal case.
"Liberia continues to be the most affected country, reporting more than 200 cases a week for the past three weeks. Transmission remains very intense in Lofa county, as well as in Montserrado county, which includes the capital, Monrovia," the report states.
It says the case-fatality rate is 53% overall and ranges from 39% in Sierra Leone to 64% in Guinea. It also notes that some Ebola treatment center beds have been added in the past week, but the capacity remains critically short.
Meanwhile, a WHO official said that at the current rate of growth, West Africa could be seeing thousands of new cases per week by early October, instead of the hundreds of cases in recent weeks, according to a Canadian Press report today.
The projection came from Christopher Dye, DPhil, an epidemiologist working in the office of WHO Director-General Margaret Chan, MD, MPH, according to the story. He said it's not clear that the epidemic's growth will reach that level. Because it is far bigger than any previous Ebola outbreak, experts are uncertain how long it will continue to expand.
"We just don't have a sense of what the maximum number of cases could be under these circumstances," Dye said.
Blood products called promising
Blood or serum from survivors has been used to treat various infectious diseases, as it contains antibodies to the target pathogen.
Kieny said experts at the WHO meeting discussed the use of both whole blood and purified plasma. "There was a consensus that this has a good chance to work and can be produced now from the [affected] countries themselves," she said, adding that the countries will need help establishing the capacity to use the approach safely.
"With the very negative point that we have so many patients, the one positive point is that there are people now who are convalescent who have survived and are doing well, and they can provide blood and serum to use," she said.
When she was asked whether the capacity to use blood product will be in place before the end of the epidemic, which the WHO has said may last 6 to 9 months, she said, "There's no doubt that convalescent serum will be used well before the end of transmission, so this is something that is near term."
A Nigerian official who spoke at the press conference, Dr. Oyewale Tomori, DVM, PhD, professor of virology at Redeemer's University, Redemption City, said convalescent serum from Ebola patients was used in an Ebola outbreak in 1995 in Kikwit, Democratic Republic of Congo (DRC).
Kieny said whole blood transfusions have been used to treat Ebola in the past, but she couldn't say in how many cases. "We'll try to get a better idea about these data in coming weeks," she added.
Recombinant vaccines
The two vaccines considered most promising are recombinant ones made from a chimpanzee adenovirus and a vesicular stomatitis virus, according to the WHO. They have been engineered to express Ebola virus components.
Kieny predicted that the results of the pending safety trials should be available in November. "After that these vaccines will start to be rolled out in affected countries, starting with healthcare workers and other front-line staff."
One vaccine trial will take place in Mali. Samba Sow, MD, director-general of the Center for Vaccine Development-Mali in Bamako, who spoke at the briefing, said the aim is to recruit 40 volunteers between the ages of 18 and 50 by early October.
Mali, which borders Guinea, was chosen for the trial because it has no Ebola outbreak yet and because his research center has experience conducing vaccine trials, Sow said.
He said front-line health workers will be used in the trial. Noting that he has worked with suspected Ebola case-patients himself, taking swabs for testing, he said, "I'm ready to be the first participant. I would love to be the first African."
Outlook for experimental drugs
Kieny said that between 5 and 10 experimental Ebola "molecules" (drugs) are under consideration. They can be tested only in the affected countries, she said.
Plans call for parallel testing of drugs at several sites, with informed consent from the patients, she said. "After 100 or 200 treatments, there can be definite conclusions about whether they bring benefit to the patient or not."
As for the time frame, Kieny said, "I think we should have an evaluation in a few months." The WHO has stressed that supplies of the experimental drugs are very limited.
Kieny said the use of statins—cholesterol-lowering drugs that have anti-inflammatory properties—was discussed at the meeting. Some experts thought they might be worth trying, but most had some concern that they might actually do harm.
Another option the experts discussed was interferon. "The experts' opinion was that if some investigators want to try interferons, they should try it in pateints with early disease, not in those with a lot of fever," Kieny said, adding that it would be up to individual clinicians to develop protocols.
American doctor evacuated
In other developments, Rick Sacra, MD, an American missionary doctor who became infected with Ebola while working in Liberia, was brought to the Nebraska Medical Center in Omaha early today after his evacuation from Africa, according to the Associated Press (AP).
Sacra, who serves with the North Carolina-based charity SIM, worked in an obstetrics ward of SIM's hospital in Monrovia. Since he didn't treat Ebola patients, it is unclear how he became infected.
Also today, Democrats in the US House requested Republican committee chairs to hold a hearing on the Ebola epidemic, citing the recent warning from the director of the Centers for Disease Control and Prevention (CDC) that the epidemic is "spiraling out of control."
The request was made in a letter signed by Rep. Henry Waxman, D-Calif., ranking member of the House Energy and Commerce Committee, along with two other Democratic leaders. They said the hearing should consider whether the CDC and other national and global health agencies have adequate plans and resources to control the disease and whether US hospitals have sufficient plans and capacity to deal with any Ebola cases that may surface.
See also:
Sep 5 WHO statement on outcome of meeting
Sep 5 WHO Ebola situation report
Audio recording of WHO press conference
Sep 5 Canadian Press story
Sep 5 AP story
Sep 4 letter from congressional Democrats
