Inside the study for a remedy to fight Congo’s deadliest Ebola outbreak

Experimental Ebola Prevention Pill Enters Critical Trial in Eastern Congo

Activelifezero.com – An experimental antiviral pill is being tested in eastern Congo as health teams search for ways to protect people exposed to the country’s rapidly expanding Ebola outbreak before they become ill.

More than 250 people have joined the study, which focuses on the Bundibugyo virus, the strain behind the current emergency. There is no approved vaccine or treatment specifically for this virus, making the trial an important effort to develop another layer of protection for people at greatest risk.

The outbreak was declared in mid-May and has since produced at least 8,300 confirmed infections and 4,000 deaths. It has reached seven provinces, while efforts to identify contacts and contain transmission continue to face major pressure.

A study aimed at preventing illness after exposure

The trial began in July in Ituri province, the center of the outbreak. It is examining obeldesivir, an investigational antiviral tablet made by Gilead. Participants receive the drug shortly after a suspected exposure to the virus, with the aim of stopping Ebola disease from developing.

This strategy is known as post-exposure prophylaxis, or PEP. Rather than treating an established Ebola infection, it is intended for people who may have encountered the virus but do not yet have symptoms.

ALIMA, a medical nonprofit coordinating the study, plans to recruit close to 1,000 adults and children older than 12. Eligible participants must have had contact with a confirmed Ebola patient within the previous five days and must not be showing signs of illness. Half of the volunteers will receive a placebo.

Each participant is monitored in person every day for 21 days. A final telephone follow-up is scheduled for day 42. If a volunteer begins to show symptoms, supportive medical care is to be provided immediately. Early supportive treatment has been shown to help Ebola patients.

Dr. Guilavogui Jean Paul Yassa, ALIMA’s research coordinator, said the approach fills a different role from vaccination or treatment after illness begins.

“It differs from a vaccine, which may take days or weeks to provide protection. It is also different from curative treatment because it is intended for people who are not yet showing symptoms,” ALIMA research coordinator Dr. Guilavogui Jean Paul Yassa said.

If obeldesivir proves effective, it could offer a practical way to interrupt chains of infection among close contacts, including relatives caring for sick family members and health workers providing frontline care.

Families and health workers face the closest risk

Volunteers include people exposed during the current outbreak, such as medical staff and relatives of patients. One participant, who joined the trial in August after her husband tested positive, said no one else in her family had developed symptoms so far.

“I realized that if I even touched my husband — and I did touch him, his vomit, everything — (it meant that) I was a direct contact. I could have also passed on this contagious disease. I could have been contaminated,” the participant said.

She described knowing households in which multiple people became infected after one relative tested positive. Participants asked not to be identified because of the highly sensitive circumstances surrounding Ebola exposure and the study protocol.

Another volunteer said two relatives had contracted Ebola and that one had died.

“This disease is killing. It’s better to take precautions,” he said.

Ebola spreads when an infected person has developed symptoms. That makes tracing close contacts a central part of controlling an outbreak: health teams must identify people who may have been exposed, monitor them during the incubation period and act quickly if symptoms appear.

In Congo, locating those at risk of carrying the Bundibugyo virus has been especially difficult. The scale and pace of the outbreak have complicated contact-tracing work, even as the disease continues to spread beyond its original area.

Emotional strain can disrupt participation

Doctors at the trial site say many people are willing to enroll, but participation can be difficult to sustain. Reaching people who live far from the health center is one obstacle. Grief and shock can create another.

Dr. Jacques Zawadi, an investigating physician working with ALIMA at the center, said some participants struggle to continue after learning that a relative has died.

“This is the biggest challenge we face. When a person is emotionally affected, it is not easy to reason with them and ensure they return to the study,” he said.

The trial also involves Congo’s National Institute of Biomedical Research and ANRS Emerging Infectious Diseases, a French institute. Its results could help determine whether an oral antiviral can reduce the risk of Ebola illness among exposed people during a severe outbreak.

Meanwhile, Congo has begun vaccinating health workers with Ervebo, a vaccine that proved effective in earlier outbreaks caused by a different and more common Ebola virus. Authorities have said Ervebo may provide some level of protection against Bundibugyo, but research is still examining whether it can prevent illness from this strain.

For communities confronting repeated exposure, the distinction matters. Vaccines may require time to build protection, while a preventive antiviral could potentially be used in the urgent days after contact with a confirmed patient. The ongoing study is designed to establish whether that possibility can become a reliable tool in the fight against Ebola.