Researchers at the University of Liverpool have found that heightened airport screening for Ebola are likely to miss many cases because of the long 21-day incubation period of the virus.
 

The findings, published in the Lancet medical journal, are based on a mathematical model to test the probability of infected travelers from West Africa entering the U.S. and the U.K.
 

The research estimated that about 29 Ebola-infected people are expected to try and leave West Africa by the end of the year and 10 would be likely to display signs of the infection that could be picked up by airport screening — such as fever and gastrointestinal distress.
 

Of the remaining 19 passengers, one or two would be expected to fly to the U.K. and up to three to the U.S. — and not all would be having symptoms.
 

“We developed a mathematical model to consider how long people incubate the virus alongside how likely airline passengers are to be infected,” said Jonathan Read, M.D. “From this we were able to estimate that 10 of the 29 people likely to leave West Africa via airports this year would have symptoms of the disease and so could be detected at exit screening.”
 

Researchers said the most effective way to restrict Ebola’s global spread is to control the disease at the source in West Africa.
 

“This research shows that entry screening can reduce the overall chances of Ebola being brought into the UK, but that some infected passengers may still get through undetected,” said Tom Solomon, head of the Institute of Infection and Global Health. “Even if we do see a case of Ebola that has not been detected at airport screening we have a good chance of stopping the spread of the infection.”