New cases per day

Different countries have responded very differently to the covid-19 pandemic, and this is reflected in the number of cases they have experienced.

Cases are currently rising in many countries and the UK is currently (data of 29 Sep 2020) the seventh worst out of the larger European countries, with a case doubling time of 14 days:

Trends in epidemics are often easier to see when logarithmic plots are used - as in the following chart:

The typical picture is that
  • cases rose rapidly in most countries
  • strict measures were imposed which halted the rise in cases, and resulted in gradual declines
  • the measures were then relaxed too far and too soon so that cases are now rising again.

Cases will continue to rise until action is taken to halt transmission of the virus - the most effective being a good test-trace-isolate-support system.

There are many examples of countries that have contained the virus much better than the UK - one is South Korea:

Read more here about elimination of the virus

Geographical distribution

Cases are distributed throughout the UK. Only two local authorities (Orkney and Shetland) have had no cases reported in the last seven days (data of 6 October).

People often interpret the figures as showing that the problem of increasing cases is greatest in the north of England. But the logarithmic plot above shows that cases are rising in all areas with similar doubling times (similar slopes on a logarithmic chart).

Why count cases?

Sometimes, people ask why count cases rather than admissions to hospital or deaths (on the basis that serious illness and death are the more important than cases with minor symptoms).

The reason is that cases are the best measure of whether we are winning or losing against the virus. If cases are rising, then admissions will rise soon after and deaths will rise soon after that. Basing decisions on admissions or deaths means delaying action, and increasing the total number of deaths, long term health problems and economic damage. Also the lower numbers of admissions and deaths means greater proportional day-to-day random variation, and so trends are harder to pick up, adding to delays in taking effective action.

The charts were generated by the online chart-drawing facility at Up-to-date charts can be obtained from there.

First published 23 Mar 2020
Last updated: 7 Oct 2020