UN chief Ban Ki-moon has said discrimination against aid workers who return home from the Ebola crisis in West Africa is "unacceptable".
Strict quarantine rules are hampering aid efforts when more health workers are needed in order to deal with the crisis, he told BBC News in Nairobi.
International efforts have been insufficient but are now "catching up", the UN secretary general added.
"We have been really trying to mobilise in a massive way," he said.
Mr Ban told the BBC's Dennis Okari that the World Health Organization (WHO) and scientists around the world were trying to develop vaccines.
The UN's main objectives included stopping the virus, finding a treatment and preventing the spread of Ebola, he said.
The medical charity Doctors Without Borders (MSF) warned on Thursday that some mandatory US state Ebola quarantine measures were having a "chilling effect" on its work.
"There is rising anxiety and confusion among staff members in the field over what they may face when they return home upon completion of their assignments in West Africa," executive director Sophie Delaunay, told Reuters news agency.
One of the charity's volunteers defied orders by the US state of Maine that she remain quarantined in her house after being in Sierra Leone.
The nurse, Kaci Hickox, who recently returned to the US from treating Ebola patients in Africa, argued that the measure contravened her civil rights as she does not have the virus.
In what her lawyer called "a terrific win", a judge has now ruled simply that she should co-ordinate travel with officials so that she can continue to be monitored, and she must report any symptoms.
"I am very satisfied by the decision," Ms Hickox told reporters, praising a "good compromise" that "offers human treatment to health care workers coming back".
US President Barack Obama has warned that overly restrictive measures could discourage volunteering in West Africa.
In other developments:
- A UK ship arrived in Sierra Leone carrying food, medical equipment and 32 pick-up trucks to help keep hard-pressed Ebola treatment centres in operation
- Speaking in Brussels after a trip to West Africa, US ambassador to the UN Samantha Power said the world must do more to confront "the greatest public health crisis ever"
- North Korea instituted a 21-day quarantine for any foreign national arriving from any country
- The World Bank said it would immediately provide $100m to fund the deployment of more health workers to West Africa