Nigeria must complete a 42-day monitoring period before it can be declared free of Ebola, despite having no active cases following the evacuation of its only confirmed patient to Switzerland, the World Health Organisation (WHO) has said.

Chikwe Ihekweazu, executive director of the WHO Health Emergencies Programme, said health authorities must monitor all 53 identified contacts of the patient for 21 days, followed by a further 21-day period, in accordance with established protocols.

Speaking in an interview on Wednesday, Ihekweazu explained that the monitoring period was necessary to establish that no further transmission had occurred before Nigeria could be declared Ebola-free.

Read also: Ebola: NCDC says 2027 elections may be postponed if outbreak worsens

The clarification follows a statement by Mohamed Janabi, WHO regional director for Africa, who said on Monday that Nigeria had no active Ebola cases after the infected patient and her husband were medically evacuated to Switzerland.

Janabi said the patient was clinically stable after receiving treatment from Nigerian medical personnel, while Swiss authorities would take responsibility for her continued care and monitor her husband, who was identified as contact number 53.

“The Nigerian medical team successfully managed her through the acute phase of the illness and stabilised her condition,” he said.

“With the evacuation of the patient and her husband, Nigeria currently has no Ebola cases,” Janabi added.

He noted, however, that Nigerian health authorities would continue monitoring the 52 contacts remaining in the country, while Swiss authorities would oversee the patient’s husband.

Explaining the next steps, Ihekweazu said the 42-day period was part of the standard procedure for confirming that an Ebola incident had ended.

“What it means still is that we have about 53 people, contacts, individuals with whom that individual had contact over the days that she was ill. And now we have to continue to follow each of them for 21 days and then require another 21 days, coming up to 42, in order to declare Nigeria Ebola-free,” he said.

“These are the standard protocols as defined by the World Health Organisation, where I work, and which we use in every country around the world that has a similar incident.”

Read also: Nigeria free of active Ebola cases after evacuation of index patient – WHO 

The WHO official also dismissed suggestions that the patient’s evacuation reflected shortcomings in Nigeria’s capacity to treat Ebola.

He said the decision followed a request from the patient’s country of origin rather than any failure in the management of the disease by Nigerian health workers.

“On Tuesday we saw the medical evacuation of the patient from Nigeria to the country from which the patient came. This wasn’t a response to any deficit in the management capacities in Nigeria,” Ihekweazu said.

“This was at the request of the country of origin of the case. She was medically evacuated yesterday, as we all saw”, he added.