Geneva - Screening passengers for Ebola on their arrival may have "a limited effect" in stopping the virus spreading but whether it adds anything to exit screening from affected countries is a decision for governments, the World Health Organization said on Thursday.
The advice from the WHO's Emergency Committee on Ebola came a day after the United States said travellers from three West African countries at the heart of the epidemic must fly into one of five major airports for enhanced screening for the virus.
"Entry screening may have a limited effect in reducing international spread when added to exit screening, and its advantages and disadvantages should be carefully considered," the committee said in a statement after its third meeting.
Passengers are already screened as they leave Liberia, Sierra Leone and Guinea, a measure that is critical for reducing the exportation of the virus, it said.
The committee of experts, which meets virtually to advise WHO Director-General Margaret Chan, said some countries had introduced entry screening and they should share their experiences and lessons learned.
Also read: North Korea steps up Ebola measures
States should be aware that screening incoming passengers helped to sensitise individuals to the risk of the disease, but "resource demands may be significant", even if only targeted screening is put in place.
The outbreak has killed at least 4,877 people and at least 9,936 cases of the disease have been recorded, the WHO said on Wednesday, but the numbers are known to be under-reported and the true death toll may be three times as much.
The committee also said some states with no Ebola cases had cancelled international meetings and mass gatherings, which the committee did not recommend. It acknowledged, however, that such decisions were complex and should be decided on a case-by-case basis and on the basis of risk.
Competitors and delegations from countries with Ebola transmission should not be subject to a general ban on attending events abroad, although the host country should decide on a case-by-case basis, it said.
Several countries, including Haiti, Dominican Republic, Colombia, Jamaica and North Korea, have restricted incoming travellers to some degree, although the committee has said there should be no general ban on international travel or trade. It reiterated that advice on Thursday.
"A general travel ban is likely to cause economic hardship, and could consequently increase the uncontrolled migration of people from affected countries, raising the risk of international spread of Ebola," it said.
"The Committee emphasized the importance of normalizing air travel and the movement of ships, including the handling of cargo and goods, to and from the affected areas, to reduce the isolation and economic hardship of the affected countries."