Twenty-one days
The Bundibugyo Ebola outbreak has passed 10,000 confirmed cases and reached Kenya and Nigeria. There is no approved vaccine or treatment, and American rules turn on a 21-day window.
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read by an AI voiceThe Ebola outbreak caused by Bundibugyo virus is now the second-largest on record, according to the Centers for Disease Control and Prevention. As of Oct. 28 the CDC counted more than 10,300 confirmed cases and nearly 5,000 confirmed deaths, almost all of them in the Democratic Republic of the Congo. In October travelers carried the virus to Kenya and Nigeria. From the night of Nov. 3, everyone boarding a flight to the United States must attest that they have not been in Congo in the previous 21 days.
The World Health Organization's most recent Disease Outbreak News, published on Oct. 23 with data to Oct. 20, puts Congo at about 9,700 confirmed cases and 4,700 deaths in eight provinces, with Ituri and North Kivu the most widely affected. Nearly half of confirmed patients have died. The figures are confirmed cases only, since Congo's official count leaves out probable cases and, for now, suspected ones, the CDC notes. In late August the WHO welcomed the end of Uganda's outbreak, which had counted 20 confirmed cases. France treated one patient, a health or aid worker back from Congo.
Kenya's first patient fell ill in Congo and traveled to Kenya through Uganda on Oct. 3. The eight cases that followed were all linked to that patient, and four were health and care workers. By Oct. 23 Kenya had counted nine cases and two deaths, the CDC reports. In Nigeria, a woman who had flown from Uganda to Abuja, also on Oct. 3, was admitted to hospital on Oct. 11 and tested on Oct. 19, after officials learned of her travel. Most of the 44 contacts first identified were health workers.
There is no approved vaccine or specific treatment for Bundibugyo virus, the WHO says. It is one of several ebolaviruses, and the vaccine and antibody drugs the Food and Drug Administration has approved are for another, Zaire ebolavirus. The vaccine, Ervebo, is not expected to protect against Bundibugyo, the CDC said in May, and the efficacy of the two antibody drugs, Inmazeb and Ebanga, has not been established against other species. The WHO says some findings suggest possible cross-protection from Ervebo, but the evidence cannot show whether it meaningfully protects people, and it recommends using it only within research protocols. With intense supportive care and fluid replacement, death rates may be lowered, the CDC's advisory says.
In Congo, a treatment trial sponsored by the WHO had begun enrolling patients by early July to test an antibody, MBP134, from Mapp Biopharmaceutical, and Gilead's antiviral remdesivir. A vaccine trial, Tumaini, registered for about 3,600 people, enrolls contacts of newly confirmed cases. Each participant is assigned at random to a candidate vaccine or a comparison shot and receives the other four weeks later, so all are offered a candidate. Enrollment began in Bunia on Oct. 23, the WHO says. The first shot given in the trial was Ervebo, Agence France-Presse reported, with a vaccine from the University of Oxford and a messenger RNA vaccine from Moderna expected to follow.
No case linked to the outbreak has been reported in the United States, the CDC says. An American missionary doctor infected while performing surgery in Bunia was flown to Berlin for treatment in May and released after recovering in June. In July a second American infected in Congo, an aid worker, was transferred to Germany, ABC News reported. Under a CDC order issued on May 18 and last renewed on Oct. 11, foreign nationals, green-card holders included, who have been in Congo, Uganda or South Sudan in the past 21 days may not enter, with some exceptions. Travelers who were in Congo in that window, Americans included, cannot board flights to the United States. Americans who were in Uganda or South Sudan in that window are routed through Dulles, Atlanta or New York's Kennedy airport for screening and asked to watch their health for 21 days.
The CDC rates the overall risk to the American public as low and says its entry order is necessary to protect the country from the serious risk of Ebola's introduction. The WHO advises against any restriction of travel to or trade with affected countries. Its director-general declared the outbreak a public health emergency of international concern on May 17, and the temporary recommendations issued days later did not recommend suspending flights from countries with documented cases or denying entry to their travelers. After the emergency committee met again in August, the director-general determined that the epidemic in Congo still met that standard.
The CDC's advice to clinicians is in a health advisory of May 19 on the outbreak in Congo and Uganda and in its clinical guidance. The advisory asks clinicians to consider Bundibugyo disease in a patient with symptoms such as fever, headache, muscle pain, gastrointestinal illness or unexplained bleeding who had an exposure in the 21 days before symptoms began, such as direct contact with a living or dead person suspected or confirmed to have the disease, or attending funeral rituals. It asks them to test for malaria and other common causes without delaying routine care. A patient with both an exposure and symptoms is to be isolated in a single room and admitted, with staff in protective equipment, until a specimen taken at least 72 hours after symptoms began tests negative. The health department is to be called at once, testing is arranged through a consultation with the CDC, and a patient who tests positive is transferred to a regional or state-designated special pathogens treatment center.
Twenty-one days is the maximum incubation period for Ebola, the CDC notes, and the same window appears in its entry order, boarding rules, monitoring of travelers and advice to clinicians. The newest of those measures, the attestation for every passenger, takes effect a minute before midnight, Eastern time, on Nov. 3.
- The WHO's count and its emergency declarationWHO Disease Outbreak News of Oct. 23, 2026 (DON622). Democratic Republic of the Congo, as of Oct. 20: 9,704 cumulative confirmed cases, including 4,687 deaths, in 66 health zones across eight provinces (Ituri 28 of 36 health zones, Nord Kivu 17 of 34); overall crude case fatality ratio 48.3%. Kenya, as of Oct. 20: nine cases, including one death. Nigeria: one laboratory-confirmed imported case in Abuja. The Director-General determined the epidemic a public health emergency of international concern on May 17, 2026, not a pandemic emergency. After the committee's second meeting, on Aug. 18, the Director-General determined that the epidemic in the DRC continues to meet the criteria of a public health emergency of international concern but not those of a pandemic emergency (WHO meeting report, Aug. 28, 2026). The May 22 temporary recommendations did not recommend suspending flights from, or denying entry to travellers from, States with documented Bundibugyo detection. WHO advises against any restriction of travel to, or trade with, affected countries.
- The CDC's count, as of Oct. 28, 2026CDC's Current Situation page (updated Oct. 30, 2026) calls this the second-largest Ebola outbreak on record. As of Oct. 28: 10,305 confirmed cases and 4,996 confirmed deaths in all, made up of the DRC (10,274 cases, 4,992 deaths), Kenya (9 cases, 2 deaths; Kenyan Ministry of Health, as of Oct. 23), Nigeria (1 case, 0 deaths), Uganda (20 confirmed cases and 2 confirmed deaths, plus 1 probable case and 1 probable death) and France (1 case, released July 4, 2026). The DRC's health ministry does not include probable cases in its official reporting, and suspected cases and deaths have been temporarily excluded pending investigation and data standardization. CDC says the overall risk to the American public and travelers remains low and that no Ebola cases associated with this outbreak have been reported in the United States. WHO and Africa CDC welcomed the end of Uganda's outbreak on Aug. 27, 2026; 15 of its 20 cases were imported from the DRC.
- Kenya and NigeriaECDC threat assessment brief, Oct. 23, 2026: Kenya's first case developed symptoms in the DRC, travelled to Kenya via Uganda on Oct. 3 and was reported on Oct. 6; the eight secondary cases, four relatives and four healthcare workers, were all linked to it and were in quarantine when they developed symptoms; 135 contacts were being followed up as of Oct. 22. Nigeria's case travelled from Uganda on an international flight on Oct. 3, with symptom onset on Oct. 7, hospital admission on Oct. 11 and confirmation on Oct. 20. AFP and Reuters reported on Oct. 21 that the patient, in Abuja, was tested on Oct. 19 after health officials learned she had recently travelled to Uganda; that most of the 44 contacts identified were healthcare workers; and that the Nigeria Centre for Disease Control and Prevention identified the strain as Bundibugyo, which WHO also confirmed. ECDC assesses the overall risk for the general EU/EEA population as very low.
- Vaccines, treatments and a rapid testCDC's clinical guidance (May 27, 2026): there are no FDA-licensed or authorized vaccines or therapeutics for Bundibugyo, Sudan or Taï Forest virus; Ervebo is FDA-approved to prevent disease caused by Ebola virus (Orthoebolavirus zairense) and does not protect against other orthoebolaviruses. CDC's clinical guidance: two FDA-approved treatments, Inmazeb (a combination of three monoclonal antibodies) and Ebanga (a single monoclonal antibody), treat Ebola virus disease; their efficacy has not been established for viruses other than Orthoebolavirus zairense. WHO's emergency guidance of Aug. 31, 2026 recommends Ervebo only within research protocols, as off-label use; some findings suggest possible cross-protection, but the evidence remains insufficient to determine whether it gives clinically meaningful protection in humans. On July 21, 2026, FDA authorized OraSure's OraQuick Ebola 2.0 Rapid Antigen Test for emergency use: presumptive detection of orthoebolavirus antigens, including Bundibugyo, without telling the species apart, in CLIA high-complexity laboratories, and not for general screening such as airport screening.
- The vaccine and treatment trialsTumaini (ClinicalTrials.gov NCT07842107) is registered as a Phase 2/3 randomized, blinded, active-controlled adaptive platform trial of candidate Bundibugyo vaccines in contacts of confirmed cases, co-sponsored by the University of Antwerp and the INRB, Kinshasa, with WHO and CEPI among the collaborators. Contacts receive a candidate or an active comparator on Day 1 and the alternative on Day 29. Planned enrollment is 3,620; the registry still listed the status as not yet recruiting when read on Nov. 2. WHO says the trial launched on Oct. 23 with first participants enrolled in Bunia. AFP reported that the first dose was Ervebo and that Oxford's ChAdOx1 and Moderna's mRNA candidates are expected to join shortly. PARTNERS, a WHO-sponsored treatment platform trial run by the INRB, the Institute of Tropical Medicine and the University of Oxford, had begun enrolling in the DRC by July 2, 2026, when the University of Oxford announced it, with MBP134 (Mapp Biopharmaceutical) and remdesivir (Gilead Sciences), alone or in combination.
- Entry and boarding restrictionsCDC's order under sections 362 and 365 of the Public Health Service Act (issued May 18, 2026; amended May 22; continued June 21, July 13, Aug. 12, Sept. 11 and Oct. 11, the last for 30 days, to Nov. 10) suspends entry of foreign nationals, lawful permanent residents included, physically present in the DRC, Uganda or South Sudan in the past 21 days, with exceptions for U.S. military and government personnel and their families and for people exempted by customs officers or CDC; CDC says it is necessary to protect the health of the United States from the serious risk posed by the introduction of Ebola disease. Travelers, including U.S. citizens and nationals, who were in the DRC within 21 days may not board flights to the U.S. U.S. citizens and nationals from Uganda or South Sudan are routed through Washington Dulles, Atlanta Hartsfield-Jackson or New York JFK for a questionnaire, a temperature check, observation by CDC staff and enrollment in CDC text messages, and are told to monitor their health for 21 days. CDC travel notices: Level 4 for Ituri and North Kivu; Level 3 for Haut-Uele and Tshopo.
- The attestation orderCDC issued the order on Oct. 22, 2026 and an amended order on Oct. 28. It goes into effect at 11:59 p.m. EST on Nov. 3, 2026, for flights departing a foreign country to the United States. All people boarding an international flight to the United States, including U.S. citizens, U.S. nationals and lawful permanent residents, must attest that they have not been present in the DRC in the 21 days before boarding. Passengers who do not sign an attestation will not be allowed to board, and airlines are directed to refuse boarding to anyone without one unless the passenger holds a U.S. government exemption. CDC says the 21-day period reflects the maximum incubation period for Ebola disease.Source: CDC, attestation order
- What CDC tells cliniciansCDC Health Advisory CDCHAN-00530, May 19, 2026, on the outbreak in the DRC and Uganda: include Bundibugyo virus disease in the differential for patients with fever, headache, muscle and joint pain, fatigue, loss of appetite, gastrointestinal symptoms or unexplained bleeding and an exposure risk within the 21 days before symptom onset (among them contact with a symptomatic or deceased case, funeral rituals, visiting or working in a health facility or laboratory, or contact with bats); test for malaria, COVID-19, influenza and other common diagnoses; immediately isolate and hospitalize patients with an exposure risk and any compatible symptom until a negative test on a specimen collected 72 hours or more after onset; contact the health department immediately; transfer patients who test positive to a Regional Emerging Special Pathogens Treatment Center or a state-designated center. CDC's clinical guidance (May 27) adds: isolate in a single room, wear proper PPE, and contact CDC for a clinical consultation to request testing.