A vaccine against the Ebola virus, developed by Chinese scientists and being tested in Sierra Leone, has proved to be "safe, responsive with very few complaints or side effects," an official at Sierra Leone's health ministry has said.

Dr. Alie Wurie, principal investigator for Phase II trial of the vaccine, told Xinhua the vaccine had undergone its Phase I trial in China on 120 Chinese nationals and 60 Africans living there.

Results of the Phase I trial, he said, were "very positive" and demonstrated a "good safety profile" for the vaccine.

To ascertain its safety among a larger community, the research institute in China in collaboration with Sierra Leone's health ministry has carried out the Phase II test in Sierra Leone, one of the countries worst hit by Ebola.

The main purpose was to evaluate the safety of the vaccine on healthy Sierra Leoneans and the reports received so far are "encouraging" as they show the vaccine is "safe, responsive with very few complaints or side effects", Wurie said.

More than 100 healthy Sierra Leoneans aged between 18 and 50 have volunteered to take the vaccine in the test.

As for now, Wurie said, the test is targeting 500 healthy Sierra Leoneans, putting them under observation for 168 days.

Dr. Hou Lihua, a scientist from the Military Medical Science Academy in Beijing, told Xinhua all the volunteers were given a mobile phone for the hospital to monitor their health condition.

If no new Ebola cases are recorded until this Saturday, Sierra Leone will mark 21 days without a new case, half of the days required by the World Health Organization to declare free of Ebola.