The Democratic Republic of the Congo (DRC) has recorded more than 4,000 confirmed cases of Ebola, including 1,850 deaths, as health authorities intensify efforts to contain what is being described as the fastest-spreading outbreak of the disease on record. The latest figures from the DRC Ministry of Health indicate that 4,053 cases of the Bundibugyo strain have been reported since the outbreak was declared in mid-May. The outbreak has spread across 53 health zones in five provinces — Ituri, North Kivu, South Kivu, Haut-Uele and Tshopo — with Ituri accounting for about 87 per cent of reported infections.
Neighbouring North Kivu has recorded a further 11 per cent of the cases, highlighting the continuing risk of wider transmission as health authorities work to prevent the disease from spreading into additional areas. The scale and speed of the outbreak have raised concerns that the official figures could underestimate the true extent of infections, particularly amid difficulties with detection and the delivery of health services. The current epidemic is already the second-largest Ebola outbreak on record, surpassed only by the devastating 2014–2016 West African epidemic, which recorded more than 28,000 cases across Guinea, Liberia and Sierra Leone.
Against the backdrop of the worsening outbreak, experts advising the World Health Organization (WHO) have recommended that Ervebo, the only licensed Ebola vaccine, be Prioritized for inclusion in a randomized clinical trial during the ongoing epidemic. Ervebo has already demonstrated safety and effectiveness against the Zaire strain, the Ebola variant responsible for most major outbreaks. However, the current DRC epidemic involves the less common Bundibugyo strain, for which there is currently no approved vaccine. The WHO recommendation follows evidence from animal studies suggesting that Ervebo could provide some degree of protection against Bundibugyo Ebola.
In studies involving non-human primates, three out of four animals vaccinated with Ervebo survived exposure to the Bundibugyo strain, compared with only one of four animals in the control groups. An unpublished study involving ferrets also produced encouraging results. Researchers found that the research-grade version of Ervebo provided complete protection against the strain in the vaccinated animals, while all animals in the control group died within 10 days. Despite those findings, experts have cautioned against assuming that Ervebo will provide the same level of protection in humans.
The WHO’s Technical Advisory Group on Candidate Vaccine Prioritization has maintained that a vaccine specifically designed against Bundibugyo remains the preferred option for controlling the current outbreak. The group has also warned that expectations surrounding Ervebo must be carefully managed if it is used in a Phase III ring-vaccination trial, noting that its ability to prevent symptomatic disease and transmission may be limited even if it ultimately helps protect against severe disease and death. Two candidate vaccines specifically targeting the Bundibugyo strain are already undergoing early-stage human clinical trials, while work is continuing on a third candidate to bring it into human testing.
The development of a vaccine tailored to the strain is considered particularly important because Bundibugyo differs from the Zaire strain targeted by existing Ebola vaccination strategies. For now, however, Ervebo remains the only licensed Ebola vaccine available for potential use in the trial. The global vaccine alliance Gavi has a stockpile of about 500,000 doses of Ervebo and has indicated that doses will be made available to support the clinical trials. Some of the stockpiled doses are already in the DRC.
Gavi Chief Executive Officer Sania Nishtar said the scale of the epidemic was deeply concerning, warning that the outbreak could potentially become the largest Ebola epidemic ever recorded. She said the possibility that Ervebo could help reduce severe illness and deaths offered some encouragement amid the heavy toll being experienced by affected communities and frontline health workers. Containing the outbreak is being made more difficult by the broader security and humanitarian challenges facing parts of the DRC.
The country has endured prolonged armed conflict, particularly in the eastern regions where several affected areas are located. The insecurity can restrict movement, complicate access to communities and make it harder for health workers to detect cases and provide timely care. Delayed detection has also emerged as a major challenge, allowing infections to spread before patients are identified and isolated. Ebola is transmitted through direct contact with the blood or other bodily fluids of an infected person or someone who has died from the disease. This makes rapid identification, isolation, treatment, contact tracing and infection-prevention measures critical to containing outbreaks.
Health authorities have consequently stepped up public-awareness efforts, including community outreach campaigns designed to encourage residents to recognise symptoms, seek medical attention promptly and follow preventive measures. With more than 4,000 confirmed cases and nearly 1,900 deaths already recorded, the DRC faces a critical battle to slow transmission while researchers seek stronger evidence on whether an existing vaccine can provide meaningful protection against a strain for which no licensed vaccine currently exists. The outcome of the proposed Ervebo trial could therefore have implications beyond the current epidemic, potentially providing important evidence for future responses to Bundibugyo Ebola outbreaks.
Source: Al Jazeera
Author: Joyce Owusu
