Welcome to Plugging the Gap (my email newsletter about Covid-19 and its economics). In case you don’t know me, I’m an economist and professor at the University of Toronto. I have written lots of books including, most recently, on Covid-19. You can follow me on Twitter (@joshgans) or subscribe to this email newsletter here. (I am also part of the CDL Rapid Screening Consortium. The views expressed here are my own and should not be taken as representing organisations I work for.)
Last October, Slovakia ran a big experiment by testing almost its entire population twice over a relatively short period. While there was an initial large reduction in cases, it didn’t last. But they didn’t just throw their hands up. They rejigged the system. Let’s check in on how they are going.
This looks excellent; especially given the new variants now circulating. Is it because of vaccinations?
Those are proceeding but not at any particularly fast rate. Instead, take a look at testing:
And test positivity.
What this represents are PCR tests not antigen screens. So when they surge antigen tests that lead to confirmatory PCR tests that are more likely to yield a positive result.
Here is what they did according to an interview with Martin Pavelka, an epidemiologist at Slovakia’s Ministry of Health,
[T]wo to three weeks after the [initial rounds of mass testing], we had an uptick of cases again, which is expected because the intervention can’t last forever. It’s like a lockdown: the moment you open up the country, the cases will rise. The massive uptick was just before Christmas. In January we repeated the whole exercise, and we had [another] round of mass testing. We are writing a second study on this. We are still in the process of analyzing the data.
At this moment, in Slovakia, we have continuous [weekly] testing. All residents who are not isolating and who are not working from home are asked to get a test at least once a week. You get a certificate, and a negative certificate is required to enter workplaces. To go to the bank, the tax office, the post office, you need to show your negatives. And it has to be no older than seven days.
And they don’t do it the ‘easy way’:
It was a massive campaign. I think this is a limitation in larger countries that have tried to replicate it. Austria tried it and couldn’t manage. In Slovakia, 40,000 army staff supported the whole intervention. We had 20,000 medical staff because it was a nasopharyngeal [deep nasal] swab, so you have to be trained to administer it.
This is something we have been able to move away from at the CDL Rapid Screening Consortium. But kudos to Slovakia being able to do it this way at scale. And it is working on a voluntary basis:
Everything is voluntary here. The amount of policing we need ... is just not possible. But Slovaks are highly scared of the virus—much more than, let’s say, in the Czech Republic. In the first wave [here], I was very surprised that everyone started wearing face masks overnight. No one questioned that.
People are asked to self-isolate for 14 days, together with all their household members. This is the second most important finding of our mathematical model: we tried to find what it is, specifically, that makes the mass testing successful. We had two scenarios in our model. We had a scenario in which all the household members would quarantine if they had a positive case. And in this scenario, one round of mass testing was enough to bring the prevalence down by [the observed] 58 percent. Then we had a scenario in which only the infected person would quarantine, but the household members would not. In this scenario, we couldn’t find any measured effect. While our model says that one round of testing is enough to observe such rapid suppression of prevalence, we know there must have been an effect of lockdown in play, because not all households were isolating [to the extent] our model demanded.
So isolation is voluntary — including family members and that works — while you need a certificate to enter workplaces and other things.
The benefits of all this are potentially huge:
It’s especially useful if things get out of control. When you suddenly have an outbreak, or you have a huge superspreading event, and you get a very high growth rate, it is a perfect intervention. You basically put people into a one-week lockdown, and then you test them. You could test a state; you could test a city. And this brings things back to normal—you could decrease [cases] by 50 percent. And then you can bring back the usual test and trace, you can bring back the conventional methods, when the epidemic is at a more stabilized, more manageable level.
The second thing is: it does actually bring you a little bit more freedom. I mean, you can’t keep people in lockdown forever. They will experience COVID fatigue. People will find ways to get around the rules. From my own experience, [in Slovakia], we have officially closed gyms, but I know of at least three gyms in my district that are open. Still, our cases are going down. [So the testing] brings people at least some degree of freedom.
But how did Slovakia manage it? This is the biggest clue that interests me:
How did this mass-testing program start?
It was basically just an idea. But because we’re a small country, it’s much easier to execute ideas. There are institutions that discuss it—there are, like, five epidemiologists in the whole of Slovakia [in charge of these decisions]. We sit down every Thursday, and, basically, we decide. All this happened within two weeks. We asked the army to organize it.
There are five people who decide. That’s it. I’ll follow up on this tomorrow but that, I think, potentially makes a big difference.