A study of nearly 100,000 coronavirus patients has shown no benefit in treating them with anti-viral drugs hydroxychloroquine and chloroquine and even increased the likelihood of them dying in hospital.
Hydroxychloroquine is normally used to treat arthritis but pronouncement from public figures including US President Donald Trump - who announced this week he is taking the drug - has prompted governments to bulk buy the medicine.
Chloroquine is an anti-malarial. Both drugs can produce potentially serious side effects, particularly heart arrhythmia. Authors of a study published in The Lancet said they found that the two medicines had no effect on the outcome of patients hospitalised with Covid-19.