from the current outbreak of Ebola have been health care workers. In this particular phase of the study, none of the participants have received a placebo.
Dr. Seydou Sissoko, a pediatrician in Mali was the first volunteer to be inoculated in Mali on October 8 in the capital Bamako. The were 10 other health care workers vaccinated on November 4th, including Dr. Samba Sow, the director of the Center for Vaccine Development (CVD) in Mali. This group was vaccinated with twice the amount of the vaccine used in previous doses given, in part to find the most effective dose. Dr. Sow says that after two weeks, some immune response is evident and there are no apparent adverse reactions.
This vaccine is kept at -8°C in a freezer, and the vaccine is brought out to thaw at room temperature for about 20 minutes prior to vaccination. This particular vaccine is different from many others in that it is a not a weakened live Ebola virus, but a modified cold virus from chimpanzees, used as a carrier for a single Ebola protein. It would not give the recipient Ebola, but perhaps a type of common cold. Dr. Sow says this is a tried and proven adverse reactions.
Those that receive the vaccine have blood drawn prior to inoculation and are closely monitored for the first hour after vaccination. Blood samples are drawn again a day after vaccination, then two weeks and 28 days later. White blood cells are examined for signs of antibodies, but then the samples have to be sent to a University of Maryland laboratory in Baltimore in the US for more sophisticated analysis to determine if this antibody response provides any immunity specific to Ebola.
This study targets health care workers who are most at risk in treating the disease. So far, there has been only one reported case of Ebola in Mali of a 2-year-old girl who traveled from Guinea, and then subsequently died. It is too early to say whether this will spread throughout Mali. She has been the only case of the disease known in Mali as of November 6. It is not yet certain whether this has spread to others in Mali due to the incubation time for the disease, generally thought to be up to 21 days.