by Trader » Fri Dec 24, 2021 9:31 am
Ok, story time....
Its Friday 24th of December, you've just woken up after getting home late last night; you'd been at Adelaide Oval watching the strikers get pumped and had to sink a few beverages to get you to the point you stopped asking why you bother attending. You get a message from your mate, encouraging you to attend The Ed for the usual Chrissy Eve session. "A few beers might help stave off the impending hangover" you think to yourself. But then you remember, mum told you Grandma's coming to Xmas lunch tomorrow. She's getting on and there's a good chance she won't make next year's. You've clearly been told, you're expected to be there, and in a reasonable shape. The last three times you've done The Ed on Dec 24th, you haven't made it out of bed on the 25th. Conflicted, you decide to run the numbers to determine what the best course of action is.
You log in and check out the dashboard from SA Health.
December 23rd - 484 new cases. Hmmm, that sounds high.
So that's the cases reported on the 23rd, which were results received in the previous 24 hours, ie December 22nd results. Swabs are taking between 24 and 60 hours to return results at the moment, lets split the middle and call it two days, so 484 cases were found from tests taken on or around December 20th.
Then you think a little more, people are being asked to get tested when the develop symptoms. Symptoms are presenting between 3 and 7 days after exposure, split the middle and call it 5 days. So 484 cases were caught in SA back on the 15th of December.
Well, what's the growth rate. You do some googling, every 2 days it doubles apparently. Is that real? Who knows. What did we report on the 21st?...145. Hmmm, we might be tripling every 2 days, not doubling! Anyway, lets assume SA is no worse than the rest of the world and work on doubling every two days.
So 484 cases caught on Dec 15th... Double it means 968 cases on the 17th...1936 on the 19th...3872 for the 21st....7744 on the 23rd and a massive 15,488 cases will be caught on Christmas day.
Active cases will be the cases caught on that day and the previous 7-10 days (by the time you catch it, develop symptoms, get your results then go into iso). Call it 8 days. So active cases will be the sum of the previous 8 days...50,820.
Holy Crap you think to yourself. There will be 50 thousand active cases attending Christmas Parties around Adelaide tomorrow?
There's 1.5m people in SA. That means there are slightly more than 1 in 30 people in SA positive and out in the community on Chrissie day.
Or to put it another way, each person active tomorrow, has a 3.39% chance of being positive without knowing it.
You then think, geez, mum's invited a few tomorrow. There's aunty shaz and her deadbeat boyfriend. Uncle Bill and his 4 kids are all coming. At least you like a couple of your cousins. Then there Nan and two of her friends that have no where else to go. Not to mention your three siblings and the 7 nephews and nieces. Oh, and a few plus ones. There's going to be roughly 25 people here.
Well if each individual has a 96.61% of not having covid, what's the chance all 25 don't have covid...0.9661^25 = 0.4225, or 42.25% chance no one has it. That means a 57.75% chance at least one of the guests has it.
Hmmm.... a 57.75% chance someone has covid at tomorrow's lunch? Sh!t, we're going to kill Grandma.
A moment of clarity dawns on you.
Be a hero, help save Nan's life, skip the Christmas lunch.
You text your mate back. "I'm in, cya at The Ed at 11am".
Danny Southern telling Plugga he's fat, I'd like to see that!