Up to 30,000 people could have been eligible for drugs in the current Ebola outbreak - if they had been available, a report in Nature suggests.

Cases of Ebola have been seen in Liberia, Sierra Leone, Guinea and Nigeria

Experts used data from previous outbreaks to work out how many family members, medics and others would have contact with infected people.

The World Health Organization recently permitted the use of experimental Ebola drugs.

But there are only enough supplies to treat just a few of those infected.

Preventing and treating

Official figures suggest more than 1,000 people across west Africa have died from Ebola in the last nine months - a number that is likely to "vastly underestimate the size of the problem" according to the World Health Organization.

And this uncertainly makes it difficult to predict the volume of medicines required to either treat infected people or protect those at risk.

Using data available from previous episodes of Ebola, researchers at the University of Oxford built a statistical model to estimate the number of people who may require medication.

Past infections mostly involved rural populations across central and East Africa - in contrast to this more quickly-spreading outbreak which has reached several urban centres.

Their model suggests around 30,000 people could have gained some protection from drugs or vaccines so far.

And they identified four groups most at risk, listing them in order of urgency:

•    People who are infected and family members and carers in close contact with them

•    Medical staff and those involved in funeral practices who have may have prolonged exposure to the virus

•    Humanitarian workers and support staff

•    A contingency supply for travellers arriving in non-affected countries.

Dr Oliver Brady, the lead researcher from the University of Oxford, said policy makers and funders needed to make urgent decisions about how best to prioritise these groups.

Source: BBC