Experimental drugs are to be fast-tracked into west Africa so that they can be tested and, if they work, save lives in the Ebola epidemic, which, experts say, is spiralling out of control. Trials of vaccines are already in their early stages, with healthy British volunteers taking part in safety tests in the UK. The Wellcome Trust is committing £3.2m to set up sites, systems and facilities for drug testing across the affected countries as well.

There is major international concern over the spread of infection and the disintegration of healthcare systems under pressure from the disease. The Centres for Disease Control (CDC) in the US released new projections on Tuesday saying that in the worst scenario, if the spread of Ebola goes unchecked, there could be 1.4m cases by late January. The WHO has not projected that far ahead, but has warned that there could be nearly 20,000 cases by early November.

Healthcare systems in the three worst-hit countries, Guinea, Sierra Leone and Liberia, fragile to begin with, have largely collapsed under the strain of coping with what may prove to be one of the most serious viral disease outbreaks in modern times.

More than 40 British military and humanitarian staff have arrived in Freetown, Sierra Leone, to oversee the construction of a UK medical facility, which will be part of the £100m UK commitment to help contain the outbreak. That includes 700 Ebola treatment beds.

The news followed a meeting of the UK’s emergency committee, Cobra, on Tuesday afternoon. It was chaired by foreign secretary Philip Hammond by videolink from New York, where the Ebola crisis had been a significant topic of discussion. “It is now vital that the international community translates its concern into action,” said Hammond. “This outbreak has wide-ranging humanitarian and security consequences for the region, and the world. Defeating this disease will need a global coalition, as well as innovative approaches to reducing the spread of the virus in communities.”

An analysis of the first nine months of the outbreak in the New England Journal of Medicine shows that the death rate is 70%, not 50%, when deaths outside hospitals are counted. Many people are too frightened to go to hospital and the number of infections is doubling every few weeks. As of 20 September, the WHO said there had been 5,843 cases and 2,803 confirmed deaths.

Some questioned the CDC projection of 1.4m cases by January. “It’s a big assumption that nothing will change in the current outbreak response,” said Dr Armand Sprecher, an infectious disease specialist at Doctors Without Borders. “Ebola outbreaks usually end when people stop touching the sick. The outbreak is not going to end tomorrow, but there are things we can do to reduce the case count.”

A call from the UK government for NHS volunteers to go out and help has so far led to 164 healthcare staff signing up. A similar appeal at the London School of Hygiene and Tropical Medicine by its director, Professor Peter Piot, has resulted in 35 staff volunteering so far. There is a particular need for trained nurses, clinicians, diagnostic laboratory technicians and sanitation experts, Piot told the school.

Experts fear that Ebola could become endemic in west Africa, instead of a viral disease that emerges from animals to cause outbreaks and then disappears again. If that happens, the region could be a reservoir for the spread of the virus, not only to other parts of Africa, but also the rest of the world, said Piot and Jeremy Farrar, the director of the Wellcome Trust, in the New England Journal. They said the epidemic “seems out of control and has evolved into a major humanitarian crisis”. In west Africa “there is a very real danger of a complete breakdown in civic society”, and communities have lost faith in authority.

Societies that were being rebuilt after civil war have been devastated by Ebola and will need rebuilding once the epidemic is finally under control, said Piot, who believes the World Health Organisation has been too slow to respond. It was three months before the first cases in December last year were identified, he said. “It was another five months and 1,000 deaths until WHO declared this a public health emergency and the world started getting serious about it.”

Several different potential drugs are likely to be trialled in west Africa, including Zmapp, which has already been used on foreign doctors and aid workers with the disease. Current supplies of the drug, made from leaves of the tobacco plant, have been used up, but its manufacture is restarting.

Independent experts will decide which potential drugs are suitable for testing – there will have to be safety data before any can be given to patients and a rapid ethical review will have to be undertaken.

“It is a huge challenge to carry out clinical trials under such difficult conditions, but ultimately this is the only way we will ever find out whether any new Ebola treatments actually work,” said Farrar. “What’s more, rapid trials, followed by large-scale manufacturing and distribution of any effective treatments, might produce medicines that could be used in this epidemic. The Wellcome Trust funding will allow these trials to happen quickly, and in an ethically and scientifically robust setting.”