The WHO Says Liberia’s Ebola Outbreak Is Officially Over

The World Health Organization (WHO) declared that Liberia is officially Ebola-free today, marking a major turning point for one of the countries hit hardest by the deadly disease.

The WHO announced that there have been no new cases of Ebola for the past 42 days, twice the maximum incubation period for the disease. Since the outbreak began last March, Liberia has had more than 10,500 Ebola cases and more than 4,700 deaths from the hemorrhagic fever, according to the WHO. A total of 11,000 people have died from the disease in the region, with the highest number of deaths occurring in Liberia.

The announcement was met with celebration in Liberia, where health workers began clapping and dancing, Dr. Alex Ntale Gasasira, the WHO's representative to Liberia, told the New York Times. Liberia's President Ellen Johnson Sirleaf also met the news with relief and held a moment of silence in remembrance of the victims who died from the disease.

Related: The End of Ebola: Inside the Race to Finish Vaccine Trials in Liberia

"We will celebrate our communities which have taken responsibility and participated in fighting this unknown enemy and finally we've crossed the Rubicon," Sirleaf told the BBC. "Liberia indeed is a happy nation."

But medical officials also cautioned against early celebration and noted that Ebola is still present in the neighboring countries of Sierra Leone and Guinea. "[Liberia's] hard work could be undone in an instant," Mariateresa Cacciapuoti, the head of Doctor's Without Borders (MSF) mission in Liberia, said in a statement. "We can't take our foot off the gas until all three countries record 42 days with no cases."

Sierra Leone and Guinea both reported nine cases of the disease each this past week. Medical officials say that it is essential to turn efforts toward those two countries before the region can be completely free from the disease.

"While this milestone is important, the world must not forget that the Ebola outbreak still persists in neighboring Sierra Leone and Guinea," the White House said in a statement congratulating Liberia on reaching the 42-day mark. "We must not let down our guard until the entire region reaches and stays at zero Ebola cases. And we must all work together to strengthen capacity around the world to prevent, detect, and rapidly respond to outbreaks before they become epidemics."

Related: Guinea Ramps Up Fight Against Ebola as Outbreak Continues to Burn

MSF opened the world's largest Ebola treatment center in Monrovia, the capital of Liberia, during the peak of the outbreak between August and October 2014. Fourteen MSF workers were among the 189 health workers that died from the disease.

Although there have been no new Ebola cases in Liberia since March, officials worry that the disease could potentially resurface by being transmitted sexually. According to recent evidence, the Ebola virus can exist in a man's semen long after the incubation period has passed and the person stops showing any symptoms. Several cases of Ebola being transmitted this way were confirmed in Liberia, including the last patient to have died, who is thought to have gotten the disease from her boyfriend months after his recovery.

It's still unknown what exactly caused the initial outbreak of Ebola, but its rapid spread and devastation was aided by the lack of health services available and widespread distrust of the healthcare system in the region. According to a report by MSF, the Ebola outbreak was further worsened by the international community's slow response.

"Quite simply, we were all too late," said Henry Gray, head of MSF Ebola operations in a statement. "The world — including MSF — was slow to start the response from the beginning. That lesson has been learned, at the cost of thousands of lives, and we can only hope it will prevent the same thing happening again in the future."

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