Be a lert but not alarmed
Auckland is going back to level 2 (God willing and the creek don’t rise) on Monday. Together with my local circle of health and stats nerds, I’m viewing this with some concern. It hasn’t been very long since we had a case show up with no previously known contact to the cluster. Like, Tuesday. It’s quite possible there are still a few other people in the cluster who haven’t been found yet.
The concern is not that it will actually be dangerous on Monday to be going to work or going shopping. The number of undetected cases will be small; your chance of getting infected on Monday is tiny. The problem is, as long as there are undetected, infectious cases, your chance of getting infected on Tuesday is very slightly higher. And slightly higher again on Wednesday, and so on in exponential increase. Eventually, it may get dangerous, and stopping it then is much more costly in health and freedom and money. In Victoria today they are talking about the psychological boost of getting a day with less than 100 new cases. If we’re careful and lucky, the current testing and tracing will be enough to stop this cluster exploding; if we’re not, maybe not.
One challenge in COVID risk communication is that the risk is longer-term and social, not immediate and individual. It’s important that as many people as possible take precautions against spreading the virus: distancing, masks, getting tested if you have symptoms, working from home if that’s feasible, avoiding places with poor ventilation. But it’s not so much important for your or your family’s immediate safety: the risk is currently very low. If someone jogs past you at close range without a mask or stands a bit too close in a supermarket line, you don’t need to panic — you almost certainly won’t catch the coronavirus. On the other hand, the more people behave that way, the more chance that they outbreak will slowly get out of control. The appropriate level of care is a lot higher than the appropriate level of fear.
Ideally, everyone would be as careful as if the virus was everywhere, but nowhere near as scared as if it was everywhere. That’s a very difficult balance, and a reason for the ‘be kind’ message when it doesn’t quite work out.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »
As long as the new cases are coming from the contact list (i.e. from within the “perimeter”) they can claim that the virus is contained. Well, as long as everyone inside the perimeter is self-isolated.
The problem I see is that they are not telling us whether or not the new cases are inside or outside the perimeter. That’s vital information.
4 years ago