User Tools

Site Tools


Covid-19 exponential

why only a 3 days shutdown

I've just found out the reason that in Queensland we are only having a 3 day shutdown because of the new outbreak of the virus, its to be able to catch up with contract tracing.

hopefully the rest of this will explain why.

the news report

This article:

reported: “ A Queensland hotel quarantine cleaner who tested positive to the highly contagious UK strain of coronavirus had 79 close contacts and 689 “movements” in the community while contagious — prompting authorities to enforce a three-day lockdown.”

I don't know what “movements” are

it doesn't say so in the article, but I assume they could have only got that amount of close contacts and movements data because from the Covidsafe app.

exponential X 79

1 1

2 79

3 6,241

4 493,039

5 38,950,081

6 3,077,056,399

7 243,087,455,521

8 19,203,908,986,159

9 1,517,108,809,906,560

7 times to cover entire world's population

the above set of figures are each line above the previous line multiplied by 79.

so the first line is 1. the second line 79, 1 times 79. third line 6,241, 79 times 79 and so on.


assuming that the same thing were to happen in the 5 days the cleaning person concerned was in the community, was to happen to each of the people she was in contact with, as can be seen in the above figures, after only the same thing happening 5 times, that covers more people than then the entire population of Australia.

after 7 times it covers well over the population of the whole planet.

that's what's exponential is all about.

It won't happen

of course every person is not going to get the virus just by being in contact with other people. also not every person would necessarily be in contact with 79 other people over 5 days. but from a contract tracing point of view, the above figures show the amount of work that could possibly need to be done, to allow people know they have come in contact with someone that could potentially have the virus.


during the lockdown period people are far less likely to come into contact with 79 people. hence the reason for the lockdown.

but the above figures also shows what could possibly happen if there wasn't a lockdown

covid-19_exponential.txt · Last modified: 2021/01/09 14:11 by geoff