The World Health Organization has recommended two vaccines designed specifically against the Bundibugyo strain of Ebola for a ring-vaccination trial in the Democratic Republic of the Congo. One of them was co-developed by the University of Oxford and the Serum Institute of India. The outbreak has killed more than 5,000 people. On 5 November, a British doctor was evacuated to London with the disease, while Kenya discharged its first recovered patients.
For the first time, vaccines designed against the Bundibugyo strain of Ebola are to be tested in the middle of an outbreak. On 4 November, the WHO’s technical advisory group on candidate vaccines recommended two of them for evaluation in the DRC. WHO officials said trials could begin “within three to four weeks”, once national approvals are in place.
NSH reports the decision a day after its announcement because it could not be confirmed from a primary source in time for NSH’s 5 November edition. It has since been checked against WHO’s own release.
An outbreak without a vaccine
Ebola is not a single virus. The vaccine that helped end recent epidemics, Merck’s Ervebo, was designed against the Zaire species. The current outbreak, centred on Ituri and North Kivu provinces in eastern DRC, is caused by Bundibugyo virus, for which no vaccine or specific treatment had been licensed.
The outbreak is now about six months old and is the largest ever recorded in the DRC. It is also the second-deadliest Ebola epidemic on record, after the West African epidemic of 2014–16, which killed more than 11,000 people. Figures differ by source and date:
- DRC health ministry, 31 October (reported by AP): 10,351 infections and 5,026 deaths, a fatality rate of almost 50%. Cases were recorded in 67 health zones across eight of the country’s 26 provinces.
- UN, as of 1 November: more than 10,500 confirmed cases and 5,126 deaths.
- Elsewhere: cases have also been recorded in Uganda, Kenya and Nigeria, and one in France.
The response faces serious obstacles. Africa CDC says about 80% of new cases are arising outside known chains of contact. About a third of deaths occur outside treatment centres, where the risk of transmission at funerals and in homes is highest. Health workers have struck over unpaid wages, and a nurse was killed while responding to an alert. Dr Patrick Otim of WHO told AP that passing 5,000 deaths was “a very tragic milestone because it is just not a number”.
The two vaccines
The WHO group recommended two candidates, both supported by the Coalition for Epidemic Preparedness Innovations (CEPI):
- ChAdOx1 BDBV, developed by the University of Oxford with the Serum Institute of India. It uses the same chimpanzee adenovirus “vector” platform as the Oxford–AstraZeneca COVID-19 vaccine, which the Serum Institute manufactured as Covishield. A harmless virus is engineered to carry instructions for a Bundibugyo protein, prompting an immune response. Phase 1 safety testing began in the UK on 24 July with 50 volunteers and was extended to Uganda in early October.
- mRNA-1469, from Moderna. It delivers genetic instructions for the viral protein in a lipid nanoparticle, like the mRNA COVID-19 vaccines. Phase 1 began in Canada on 4 August.
Both will join the Tumaini trial. It was launched on 23 October and is led by the DRC’s National Institute of Biomedical Research (INRB) with the University of Antwerp, alongside WHO, MSF, Africa CDC and others. Merck’s Ervebo is also being tested to see whether it offers any cross-protection.
How ring vaccination works
Tumaini uses ring vaccination, the strategy that helped eradicate smallpox and was used in Guinea in 2015 to show Ervebo’s efficacy. When a case is confirmed, investigators identify the patient’s contacts, and the contacts of those contacts, and offer them the vaccine. This builds a protective ring around each case. Comparing infections among people vaccinated immediately with those vaccinated later, or with a different vaccine, can show efficacy quickly. The method depends on finding contacts, which is difficult when most new cases emerge outside known chains, and on safe access in a conflict-affected region.
WHO Director-General Tedros Adhanom Ghebreyesus said the readiness of the vaccines was “a testament to the power of science and partnership”. He added: “Vaccines alone will not end this outbreak, but they could become a powerful new tool for bringing it under control.” Results are expected in early 2027.
Treatment research is also under way. The PARTNERS trial is testing the monoclonal antibody MBP134 and the antiviral remdesivir, alone and together, and a study of obeldevisir as post-exposure prevention has begun.
The 5 November developments
On 5 November, a British doctor who had tested positive in the DRC was flown to the high-level isolation unit at London’s Royal Free Hospital. It is the UK’s fifth Ebola case ever. The UK Health Security Agency said the risk to the public is low. Dr Damien Tully of the London School of Hygiene & Tropical Medicine called the case “deeply concerning” but “not entirely unexpected”, noting no sign that the virus has become more transmissible.
In Kenya, five patients were discharged after recovering. The country has recorded nine cases and two deaths, all from a single imported cluster, and no new infections since 19 October. An outbreak can be declared over 42 days after the last case recovers or dies.
Why India should pay attention
The Serum Institute’s role matters most if the vaccine works. As the world’s largest vaccine manufacturer by doses, it could supply at a scale few others can match. WHO says it is discussing post-trial access with manufacturers, but no dose commitments have been announced. India’s own risk remains low, but travel links with East Africa and the Gulf mean that airport surveillance and laboratory preparedness, including at ICMR’s National Institute of Virology in Pune, remain relevant.
