The World Health Organization announced on May 9 that the Ebola outbreak in Liberia is finally over.

"Forty-two days have passed since the last laboratory-confirmed case was buried on 28 March 2015. The outbreak of Ebola virus disease in Liberia is over," WHO says in an official statement.

The agency called the breakthrough a "monumental achievement" for Liberia, which is the hardest hit country from the recent Ebola outbreak. At the peak of the outbreak in August and September 2014, up to 400 new cases were being reported every week.

Liberia has suffered the most number of Ebola-related deaths since the emergence of the virus in 1976, even reaching a point when no more beds were available anywhere for patients who needed treatment. People died on hospital grounds, and sometimes bodies remained uncollected for days, according to WHO.

The agency lauded the people of Liberia for their determination to conquer the disease. Although there were fears that Ebola might grow to be an endemic disease in Liberia, its human-to-human transmission in the country has finally been halted.

As WHO gave its official statement, Liberia president Ellen Johnson Sirleaf led the country in observing a moment of silence for those whose lives have been claimed by the virus. She expressed gratitude for everyone, local and international alike, who helped defeat Ebola in Liberia. She told the people to celebrate the victory "but stay mindful and vigilant."

The president, accompanied by WHO representative Dr. Alex Gasasira, went to visit Ebola survivors in hospitals. The health workers were rejoicing and singing shouts of "no more Ebola," according to The New York Times.

In the midst of the celebration, WHO in its official statement cautioned Liberia not to be complacent in the fight against the virus, particularly when neighboring Guinea and Sierra Leone still suffer from outbreaks.

"While WHO is confident that Liberia has interrupted transmission, outbreaks persist in neighbouring Guinea and Sierra Leone, creating a high risk that infected people may cross into Liberia over the region's exceptionally porous borders," the agency said.

WHO personnel will remain in Liberia until the end of the year to ensure vigilance against new cases that may enter from neighboring regions and to help with the needed health services.

The international response against Ebola has been criticized by many to be slow in the face of urgency.

As of May 6, there have been a total of 10,564 total cases of Ebola in Liberia, with 4,716 confirmed deaths. Guinea records 3,592 cases and 2,387 deaths. Sierra Leone has the most number of reported cases - 12,492, with 3,904 confirmed deaths, according to the Centers for Disease Control and Prevention.