Uncertainty abounds - even as we get better data on treatments, with the big RCTs beginning to report, and new trials on masks, the evidence remains uncertain, in both the statistical realm (confidence intervals crossing 0) and in what to do in the face of that continuing lack of clear effect. As always Helen Macdonald and Duncan Jarvies are looking at the evidence, and this week are joined by John Brodersen, professor of general practice at the University of Copenhagen. Helen talks to Bram Rochwerg, methodology lead on the WHO treatment guidelines for covid, about why their latest review has stopped recommending remdesivir for covid-19 treatment. John tells us about the Danmask study - what question it was actually trying to answer. We also discuss the ways in which there is a tendency to express certainty where there is none, and why distrusting simple solutions to complex problems is a good rule of thumb. Reading list: A living WHO guideline on drugs for covid-19 https://www.bmj.com/content/370/bmj.m3379 Covid-19’s known unknowns https://www.bmj.com/content/371/bmj.m3979 Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers

https://www.acpjournals.org/doi/10.7326/M20-6817