Thanks to Mary Marshall for alerting me to this article, A Plan for the Autumn, by Christian Drosten in Zeit Online. Excerpt from the Google translation:
When the Covid 19 epidemic reached Germany, the country reacted quickly and well. In hardly any other large industrial nation have so few people died of the disease. We were able to control this first wave better than many others because we were able to test early and there was greater trust between society, politics and the infection sciences than elsewhere. Our early and short lockdown saved the economy a lot of damage. It is not only in the USA that one can observe what premature and then withdrawn easing means for the economy.
But now we run the risk of losing our success. There is one main reason for this: we learn a lot of new things about the virus, but are reluctant to do so. We have to ask ourselves a few questions: What consequences do we draw from the knowledge that the virus is mainly transmitted via the air - not only via the classic droplet infection, but also via aerosols? What does that mean in autumn and winter for public buildings, for daycare centers and schools, for offices and authorities, for hospitals and nursing homes? When will we consistently wear our mask, also on our nose, not just under it? What technical and pragmatic solutions are there for an adequate exchange of air - in a country of engineers, not of those with concern? And how do we envision the use of the vaccines that are sure to be available next year? Even if they didn't offer complete protection, they would significantly slow the spread of the virus and make the disease less severe. We shouldn't be talking about that.
The challenge is to know our room for maneuver for the exceptional time that passes until the vaccination is available. An unclearly stipulated infection course could destroy our previous successes, both medical and economic.
If you want to write a meaningful recommendation for action for autumn, you first have to understand the differences between the first and second wave. The first wave arose when the virus was introduced by skiers and other travelers, who initially spread it mainly in their own age group. This was followed by the spread among the elderly, particularly in old people's homes and care facilities. Then it was already possible to control the exponential spread of the virus and thereby stop the first wave without spreading it widely.
We cannot rest on our laurels. We need to revise our concepts as our knowledge of the pathogen increases. And above all, we have to be prepared for the fact that the second wave will have a completely different dynamic.
While the virus has entered the population with the first wave, it will spread with the second wave. In the meantime, it has spread more and more evenly across social classes and the age cohorts. And after the holiday season, we will see that the new infections will be more evenly distributed than before in geographical terms.
All of this has consequences for the persecution: While most infection chains have so far been comprehensible, new cases will soon be able to occur everywhere at the same time, in all districts, in all age groups. Then the poorly equipped health authorities are finally overwhelmed with regulating the quarantine of each contact person. Many of them surrendered to this task in the first wave.
But are we therefore exposed to the second wave without protection? No. Because when you look closely, the distribution is not homogeneous, and you can take advantage of that. Infection scientists observe a surprisingly uneven distribution of the infection frequency per patient. The reproduction number R represents only an average. Taking an R value of two as an example, each patient infects two more. But only on average. In our example, nine out of ten patients only infect another, but one of the ten infects another eleven. In total, ten patients caused twenty subsequent cases.
If we do not imagine the ten infected people at the same time, but one after the other, then we have a chain of infection. Nine of the ten cases in this chain are single transmitters, and they play no role in the exponential spread of the pathogen. One of the ten has a multiple transmission, a cluster. While the chain sometimes breaks during single transfers, several new chains can start from a cluster. That means exponential growth.
