Why does Kenya wait 42 days after the last Ebola patient is discharged?

Kenya must wait 42 days after its last Ebola patient leaves treatment free of the virus because 42 days is twice the longest incubation period, the time between infection and the first symptoms. That period is 21 days. The Ministry of Health said on 6 November 2026 that the count has not started, because one of the country's nine confirmed patients is still being treated.

The World Health Organization (WHO) fact sheet on Ebola says the incubation period "varies from 2 to 21 days" and that people cannot transmit the disease before they have symptoms. WHO's notice on the Bundibugyo strain, the virus behind Kenya's outbreak, gives the same range and says people are usually not infectious until symptoms begin.

Why double the 21 days? When WHO's Africa office announced on 27 August 2026 that Uganda's Bundibugyo outbreak had ended, it called 42 days "the internationally established benchmark for determining that transmission linked to an Ebola outbreak has ended" and said the period is "equivalent to twice the upper limit of the incubation period for Ebola". It said the extra time guards against missed transmission chains from the last imported case. Uganda's count ran from the discharge of its last imported patient on 16 July 2026.

The same rule was used in the Democratic Republic of Congo (DRC) in 2017. WHO declared that outbreak over on 2 July 2017, 42 days ("two 21-day incubation cycles") after the last confirmed patient tested negative for the second time.

The starting point differs by outbreak. In Kenya, the ministry said the countdown begins when the last patient leaves the treatment centre free of the virus, and described the 42 days as "twice the longest time it takes for the illness to appear", as quoted by the Kenyan news site Kenyans.co.ke. If no new case appears in that period, Kenya will be declared Ebola-free.

The countdown is separate from the 21-day monitoring of contacts, people who were exposed to a patient. WHO advises monitoring each contact for 21 days after the last known exposure. In Kenya, 66 contacts have completed that monitoring and gone home, and 52 more are expected to finish by 11 November 2026.

Kenya's outbreak began when the first imported case was confirmed on 6 October 2026. The ministry said all nine confirmed cases are linked to that case, two patients have died and six have recovered. The last confirmed infection was on 19 October 2026, and the country had gone 18 days without a new one by 6 November 2026. Later cases were among people already in quarantine, and there is no evidence of community spread.

WHO's fact sheet says there is no approved vaccine or treatment for Bundibugyo disease, although candidate products are in development. The ministry credits early detection, isolation and treatment, contact tracing, protection of health workers and safe burials for the progress so far.

Screening continues. More than 760,000 travellers have been screened at 26 points of entry, The Star reported on 6 November 2026, and Kenya has imposed no restrictions on travel, trade or public gatherings. Travellers are asked to complete electronic surveillance forms through the UHAI Chatbot before arrival, to declare symptoms honestly and to report any illness within 21 days of entry.

Director General for Health Patrick Amoth said: "The measures put in place are working and the country is firmly on the path to ending this outbreak." He added: "Until that day, we must not let down our guard."

The ministry's health advice is to watch for fever, weakness, muscle pain, vomiting, diarrhoea and unexplained bleeding and to seek care promptly; not to touch the blood or body fluids of suspected patients or handle the bodies of people who die of unexplained illness; to avoid handling sick or dead wild animals and not to eat their meat; to wash hands regularly with soap and water; and to welcome recovered patients and released contacts back without stigma. Suspected cases can be reported on the toll-free line 719, by dialling *719# or on WhatsApp at 0700 719 719.