The head of the World Health Organization said Friday that the Ebola outbreak in Congo is “spreading rapidly” and now poses a “very high” risk at the national level. WHO Director-General Tedros Adhan...
A WHO press briefing also heard that scientists had identified an antiviral drug, obeldesivir, which may be able to prevent contacts of Bundibugyo cases developing the disease, and were working to establish trials in the affected areas.
Obeldesivir is an ester of remdesivir (converted into the nucleoside prodrug “remdesivir” by esterases once taken orally). Remdesivir is an old drug which was first approved for Hepatitis C, then for COVID-19, so there might be supplies.
If given within 24 hours of infection through mucosal membranes (e.g. mouth, nose, eyes), it protects one species of macaques against Ebola well enough to have 100% survival during 21 days (but another species only gets 80% survival).
It is predicted to protect humans, since the mechanism does not depend on the host species, but jams the viral RNA polymerase. But it works only if infection has just started, and there is very little viral RNA polymerase around in the body.
I think it will mostly find use among medical personnel, who are likely to learn fast if they have been exposed. With the wider population, it probably won’t help as much - when detection comes late, the amount of virus in the body is too great to counter, so the drug can only disable a fraction of it. It likely can’t help if symptoms are already serious, and perhaps even if any symptoms are already present. Effective use is therefore likely to depend on effective testing and tracing.
There is one bit of good news too, which I noticed here:
https://www.theguardian.com/global-development/2026/may/22/suspected-ebola-cases-triple-in-a-week-as-who-warns-of-rapid-spread-in-drc
Obeldesivir is an ester of remdesivir (converted into the nucleoside prodrug “remdesivir” by esterases once taken orally). Remdesivir is an old drug which was first approved for Hepatitis C, then for COVID-19, so there might be supplies.
If given within 24 hours of infection through mucosal membranes (e.g. mouth, nose, eyes), it protects one species of macaques against Ebola well enough to have 100% survival during 21 days (but another species only gets 80% survival).
It is predicted to protect humans, since the mechanism does not depend on the host species, but jams the viral RNA polymerase. But it works only if infection has just started, and there is very little viral RNA polymerase around in the body.
I think it will mostly find use among medical personnel, who are likely to learn fast if they have been exposed. With the wider population, it probably won’t help as much - when detection comes late, the amount of virus in the body is too great to counter, so the drug can only disable a fraction of it. It likely can’t help if symptoms are already serious, and perhaps even if any symptoms are already present. Effective use is therefore likely to depend on effective testing and tracing.