Pfizer announce Covid-19 vaccine

What do we know about Pfizer and bioNTech's new RNA-based COVID-19 vaccine, preliminary results for which were announced this week? Who was tested in the trial? And what is a genetic vaccine, why were vaccinees innoculated twice, what does 90% effective mean, and what's the reason it needs to be stored at -80º C? Joining RNZ's Kim Hill, virologist Dr Chris Smith explains... Like this podcast? Please help us by supporting the Naked Scientists