FREETOWN (REUTERS/AFP) - The World Health Organisation (WHO) on Saturday declared the end of the Ebola outbreak in Sierra Leone that has killed almost 4,000 people, including more than 200 health workers, since it began last year

Following 42 days with no new cases, the West African nation's epidemic was declared officially over at a ceremony attended by President Ernest Bai Koroma and UN WHO representative Anders Nordstrom.

Thousands of people gathered under the Cotton Tree, a massive tree in the centre of the capital, Freetown, overnight for a candlelight vigil organised by women's groups to pay tribute to health workers who died.

"They died so we could live," Fatmata, a university student, said with tears in her eyes. Many of the health workers who died were infected due to inadequate protective equipment and training.

The country's first confirmed Ebola survivor, Victoria Yillia, told the crowd she was "happy that this disease which almost killed me has finally ended". She appealed to authorities not to forget survivors, many of whom have faced social stigma and persistent health problems.

Elsewhere in the city, residents celebrated the end of the epidemic, which forced schools to close, overwhelmed healthcare systems and hurt the local economy.

"We're happy. I feel free again after a period of bondage in the hands of Ebola," said trader Joseph Katta as he clutched a pint of beer at a pub in the suburb of Lumley.

Ebola has killed more than 11,300 people in Sierra Leone, Liberia and Guinea since the epidemic was announced in March 2014 and about 28,500 were infected, according to WHO data. Sierra Leone's death toll was 3,955 people.

Liberia was declared free of Ebola on Sept 3, while a handful of cases remain in Guinea.

The 42-day countdown to be declared Ebola-free starts when the last patient tests negative a second time, normally after a 48-hour gap following their first negative test.

Fear of the virus transformed the three countries and hampered efforts in Sierra Leone and Liberia to recover from civil wars.

At the height of the epidemic, the two countries ordered everyone to stay indoors for days at a time in an attempt to identify new cases and slow the disease's spread.