In a press briefing today Professors Chris Whitty and Patrick Vallance showed epidemic curves for Spain and France — demonstrating how cases numbers have been growing rapidly, possibly exponentially, since August. As is often done when using case numbers by publishing date, the raw numbers are smoothed with a seven-day moving average. Drawn this way, the data shows a continued upward trend.
But drawing the epidemic curve for Spain using cases by symptom onset produces a different result. We have put these two methods together on a single graph so that they can be compared:
The epidemic curve based on the symptom onset date does not show the same continued growth — it appears to show cases stalling in late August.