As human trials of Covid-19 vaccines kick off in the UK, what kind of protection might we expect, and when will we know. Also, the thorny issue of facemasks - do they help contain the contagion, or not? Also, children as active 'super spreaders' of the disease, strange blood clotting effects, and a distinctive form of pneumonia caused by Covid. Dr Chris Smith joins Radio New Zealand National's Kim Hill for an update on what this week has revealed about SARS-CoV-2... Like this podcast? Please help us by supporting the Naked Scientists