The Science Hour

There's been encouraging news about the Oxford Covid-19 vaccine this week from a trial involving about 1,000 people. But how great is the challenge in scaling up from making a few thousand doses of the vaccine to manufacturing two billion by the end of this year? Sandy Douglas of Oxford's Jenner Institute explains how they plan to mass-produce the vaccine safely given the speed and magnitude of the scale up. A new kind of treatment for Covid-19 may come from an unlikely source: llamas and alpacas, the South American relatives of the camel. Camelids produce unusually small and simple antibodies against viruses, including the coronavirus. This feature may make these molecules an effective Covid-19 therapy. Jane Chambers reports on research in Chile and the UK.Also in the programme: what has made just a few mosquito species evolve a preference for biting humans, and the theory that 800 million years ago the Moon and the Earth were bombarded by a shower of asteroids which plunged the Earth into a global ice