A bit more on the news from the US, that emergency authorisation has been given for blood plasma to be used to treat coronavirus patients.

President Donald Trump told reporters he had been "looking forward" to making such an announcement "for a long time".

He called for Americans to come forward to donate plasma if they've already recovered from Covid-19.

The US Food and Drug administration says it's a safe treatment - but more trials are needed to prove its effectiveness. Early research suggests it can decrease mortality rates as long as it's given within the first three days of hospitalisation.

Those under the age of 80, who were not on a respirator and received plasma containing high levels of antibodies, had benefited the most from the treatment, said the FDA. They had a 35% better survival rate a month after the treatment than those who had received plasma with a low level of antibodies.
Some experts - including Dr Anthony Fauci, a member of the White House's coronavirus task force - have expressed reservations about the robustness of studies so far, however.

In a statement, the Infectious Diseases Society of America said that while there were "some positive signals that convalescent plasma can be helpful in treating individuals with Covid-19.... we lack the randomised controlled trial data we need to better understand its utility in Covid-19 treatment".

The World Health Organization last month said that "Covid-19 convalescent plasma can be made available on an experimental basis through local production provided that ethical and safety criteria are met for its preparation and use.