More than 250 participants have enrolled in a clinical trial in the Democratic Republic of Congo for an experimental drug designed to prevent people from contracting Ebola. Health experts describe the study as a critical step in combating the Central African nation's deadliest outbreak of the disease to date.
The clinical trial, which began in July, is targeting the Bundibugyo virus strain. This fast-moving strain is currently without any approved vaccine or treatment. The study is one of several scientific efforts launched in recent months to find preventative measures and slow the rapid spread of the virus.
The trial is taking place at a health center in Rwampara, located in the eastern province of Ituri, which serves as the epicenter of the outbreak. Participants include individuals who have experienced direct exposure to the disease during the current outbreak, such as healthcare workers and relatives of infected patients.
Since the outbreak was officially declared in mid-May in eastern Congo, authorities have recorded at least 8,300 confirmed cases and 4,000 deaths. The virus has successfully spread to seven provinces and continues to outpace tracking and containment efforts.
The study is evaluating Gilead's experimental antiviral pill, obeldesivir. It is administered shortly after suspected contact with the virus to stop the disease from developing, a preventive approach known as post-exposure prophylaxis, or PEP.
One anonymous female participant in the EBO-PEP trial shared that she enrolled in August after her husband tested positive for Ebola. She explained that she had direct physical contact with him and his vomit, recognizing that she was a direct contact who could have been contaminated and passed on the highly contagious disease. She noted that she has seen entire households become infected after a single family member tested positive, but so far, no one in her own family has developed symptoms.
Ebola only becomes transmissible once an infected person begins showing symptoms, meaning those exposed must wait to see if they fall ill. This challenge is compounded by the fact that contact tracing—finding people at high risk of incubating the Bundibugyo virus—has proven exceptionally difficult in Congo.
Another participant, who also requested anonymity to protect their privacy, shared that two of their family members had contracted Ebola, resulting in one death. They emphasized that because the disease is so lethal, taking precautions through the trial is a necessary step.
The trial is coordinated by the medical nonprofit ALIMA. The organization aims to recruit nearly 1,000 adults and children over the age of 12 who have been in contact with a confirmed Ebola case within the last five days but do not display symptoms. Half of the enrolled participants are randomly assigned to receive a placebo.
According to Dr. Godefroid Basara, a physician working on the study, participants undergo daily in-person monitoring for 21 days, followed by a final follow-up phone call after 42 days. ALIMA has stated that if any participant begins to show symptoms of the disease, they will immediately be transitioned to receive supportive treatment, which has proven effective when administered early.
If the experimental pill proves successful, it could play a major role in breaking the chain of transmission. Dr. Guilavogui Jean Paul Yassa, a research coordinator for ALIMA, explained that the pill differs from a vaccine because vaccines can take days or weeks to provide active protection. It also differs from curative treatments because it is specifically intended for individuals who are not yet showing symptoms.
Dr. Yassa acknowledged that the trial faces severe disruptions, particularly when participants learn that family members have died from the virus. He noted that when individuals are emotionally devastated, it is incredibly challenging to convince them to return and continue participating in the study.
The clinical trial is a collaborative effort that includes Congo's National Institute of Biomedical Research and the French institute ANRS Emerging Infectious Diseases alongside ALIMA.
The threat to humanitarian workers remains high. Doctors Without Borders announced that one of its staff members tested positive for Ebola and was being evacuated to the Netherlands for treatment. Additionally, an ALIMA humanitarian physician tested positive in June after returning to France from an active virus hot spot.
The World Health Organization warned that the current outbreak continues to outrun containment efforts. The agency projected that the crisis is on track to exceed the scale of West Africa's 2014–2016 regional outbreak, which stands as the deadliest on record with 11,000 fatalities.
Brennan reported from Dakar, Senegal. Lauran Neergaard contributed from Washington, D.C.
