GlaxoSmithKline says the first batch of its investigational Ebola vaccine, developed with the US National Institutes of Health, should arrive in Liberia today (January 23).

The shipment, containing an initial 300 vials, will be used to start the first large-scale efficacy trial of experimental Ebola vaccines in the coming weeks. It is currently being tested in five small Phase I studies in the UK, USA, Switzerland and Mali, involving around 200 healthy volunteers in total, and initial data show that the vaccine has an acceptable safety profile.

The selected dose will now be tested in a Phase III trial led by the NIH which will involve up to 30,000 people, one-third of whom will receive GSK’s vaccine. It will compare the latter to a control vaccine to assess whether the immune response seen in Phase I actually translates into meaningful protection against Ebola.

GSK vaccines chief Moncef Slaoui said the initial data “give us confidence to progress to the next phases of clinical testing which will involve the vaccination of thousands of volunteers, including frontline healthcare workers”.

The declining number of cases in Liberia suggests that there trial will take longer to complete but GSK has stressed its commitment to completing the study, despite the effect on its usual business. Chief executive Sir Andrew Witty told Radio 4’s Today programme that “we have delayed two other vaccine programmes to do this work”.