Limiting the rate of infections: it's all about geometric progression

News 100 blueBy Pepper Parr

August 4th, 2020



We did a photo feature earlier today with photographs showing people out and about the city not wearing masks.

A number of people thought we were wrong and told us so via their Facebook comments.

The public health objective is to reduce the rate at which infections get passed from person to person.

Meed Ward in a mask

Mayor of the city wears a mask

Wearing a face mask was made mandatory by the city in July. The bylaw was very specific – requiring people in offices and retail locations to wear a face mask.

Many think that the wearing of a mask outdoors is not necessary. Is it just a matter of personal choice or does it mean looking at the options and deciding how careful you want to be ?

The risk is certainly lower outdoors – but it is still a risk – when you add the results of geometric progression to that risk you can see why masks work.

Economist graphHaven’t heard of geometric progression? The explanation for the pattern of American infections lies in something of central importance to the spread of a virus: geometric progression, such as 1, 2, 4, 8, 16.

If one person infects two, two infect four and so on. Unless the rate of infection is driven down by reducing contacts, any geometric increase quickly balloons: 256, 512, 1,024.

The graph makes it clear that when lock downs were in place rates of infection dropped. When the Americans opened things up, in early June – and didn’t require masks – the rate of infections soared.

Simple math… 2048, 4096, 8192, 16,384 – do you want to keep going?

Return to the Front page
Print Friendly, PDF & Email

1 comment to Limiting the rate of infections: it’s all about geometric progression

  • Eleanor Bain

    Yes a mask is uncomfortable but I wear one to protect others from getting ill and passing it on to perhaps parents or grand parents or children friends or simply anyone. Would not feel right if someone died because of me being selfish and not caring for other people. Please wear a mask and help to save lives.