Our understanding of the way Covid-19 is transmitted from person to person has changed a lot since the pandemic began. A year in, here's what we now know.
Countries have a history of acting selfishly – and when they do, everyone loses out, writes Roderick Bailey. According to one recent estimate, more than half of all vaccines against Covid-19 have â€¦
If you've been sharing the beach with the odd string of salps this summer, don't be alarmed – not only are they harmless, they play a key role in our marine ecosystem.