A medic in PPE gear (Image: GETTY) "Random control trials will always have a scientific advantage and remain the most effective means of determining whether a vaccine works or not – and to what extent – but we would urge the government to investigate the role of challenge trials in future pandemic preparedness planning and when it comes to variant vaccines to address new, dangerous strains." The paper recommended Research and Development timescales should be cut. The think tank suggests this could be achieved by running phase II and III trials at the same time. The paper said: "Vaccines should take weeks, working to an ambition of 100 days from a threat being discovered to be developed and distributed."