This coronavirus app shows why flattening the curve matters

We’ve all become familiar with the official advice to protect ourselves from coronavirus: stay at home, wash your hands, and if you must go out, keep your social distance.

Now, a new interactive app based on mathematical projections for progression of the disease gives a stark illustration of why it's so important.

The 'Flatten the Curve' app shows the 'infection curve', which is a projection of how fast coronavirus cases will peak before reducing. A sliding scale on the app allows the user to increase or decrease the average number of times the disease is passed on by each sick person. When this number decreases, the infection curve flattens.

Now the technical bit. The app is based on something called the R0 number (pronounced ‘Rnought'). This is also known as the reproduction number, and indicates how contagious an infectious disease is.

It tells you the average number of people who will catch a disease from one contagious person, in a population previously free of infection and unvaccinated.

Peak number

For instance, if a disease has an R0 of 6, then a person with the disease will infect six other people, on average. If the R0 is less than 1, then the disease will die out.

The R0 value of the 1918 flu pandemic has been estimated at between 1.47 and 2.27, and that of the 2009 swine flu virus at between 1.2 and 1.6.

With COVID-19, the key to ensuring health services around the world can cope is to flatten the infection curve. This involves spreading out the peak number of cases over a longer period of time, so critical care units do not become overwhelmed.

By moving the slider on the app and changing the R0 of COVID-19, you can see what might happen to the curve during 2020.

The red peak shows what could happen without safety measures being followed, while the green scenario is determined by the average number of people infected by each sick person.

Official advice

In an ever more globalized world, the logistics of containing the pandemic are huge. The World Economic Forum, for instance, says responding to the crisis requires global cooperation among governments, international organizations and the business community. But every individual can also play their part.

And this is why official coronavirus advice matters. While the equations used to create the app may be complicated, you don’t need to be a mathematician to understand that everyone can help reduce the R0 of the virus.

The World Health Organization advises that to protect yourself and others, you should: