Category Archives: Science

“In der vergangenen Woche lag dieser stabile R-Wert an keinem Tag über eins”

Deutsche Welle: Corona-Krise: RKI führt neue R-Kennzahl ein. “Mehrere Tage lag hierzulande die Corona-Reproduktionszahl R wieder über eins. Und sie wirft wegen statistischer Unsicherheiten allerlei Fragen auf. Deshalb kündigte das Robert Koch-Institut nun eine neue Kennzahl an.”

“Wie in anderen Ländern rechnen Experten auch in Deutschland mit einer hohen Dunkelziffer nicht erfasster Infektionen. [RKI-Vizepräsident Lars] Schaade betonte daher, das Einhalten der Abstands- und Hygieneregeln sei weiterhin sehr wichtig. “Helfen Sie mit, das Virus auch weiterhin in Schach zu halten. Es ist noch da, auch wenn es deutlich weniger geworden ist”, mahnte er.”

Crashkurs zu den Daten über Corona

Quarks.de (WDR): Was die Daten zu Corona aussagen und was nicht. “Mit dem neuen Coronavirus preschen täglich neue Zahlen auf uns ein – mehr Infizierte, neue Todesfälle, dazu Berechnungen über Verdopplungsraten und Sterberate. Wir erklären, was das bedeutet, was oft falsch gemacht wird und wo die Wissenschaftler noch streiten.”

Erklärt werden Basisreproduktionszahl, effektive Reproduktionszahl, Morbidität, Prävalenz, Verdopplungszeit, Mortalität (Todesrate, Sterblichkeit), Letalität, Fall-Verstorbenen-Anteil (CFR, englisch: case fatality rate), infection fatality rate (IFR), Manifestationsindex.

“A Robust Public Health Care System”

The New York Times: A German Exception? Why the Country’s Coronavirus Death Rate Is Low. “The pandemic has hit Germany hard, with more than 92,000 people infected. But the percentage of fatal cases has been remarkably low compared to those in many neighboring countries.”

“All across Germany, hospitals have expanded their intensive care capacities. And they started from a high level. In January, Germany had some 28,000 intensive care beds equipped with ventilators, or 34 per 100,000 people. By comparison, that rate is 12 in Italy and 7 in the Netherlands.

By now, there are 40,000 intensive care beds available in Germany.

Some experts are cautiously optimistic that social distancing measures might be flattening the curve enough for Germany’s health care system to weather the pandemic without producing a scarcity of lifesaving equipment like ventilators.

“It is important that we have guidelines for doctors on how to practice triage between patients if they have to,“ Professor Streeck said. “But I hope we will never need to use them.“

The time it takes for the number of infections to double has slowed to about eight days. If it slows a little more, to between 12 and 14 days, Professor Herold said, the models suggest that triage could be avoided.

“The curve is beginning to flatten,“ she said.”

Helpful or harmful?

Ein einfaches Beatmungsgerät bauen? Das geht!. “Kreativität ist in Krisen besonders wichtig. Physiker an der Marburger Universität sind auf die Idee gekommen, Geräte aus der Schnarch-Therapie so aufzurüsten, dass damit Corona-Patienten weltweit beatmet werden können.”

The Breathing Project hat allerdings nach eigenen Angaben noch keine Zulassung für ihr medizintechnisches Produkt.

NPR: CPAP Machines Were Seen As Ventilator Alternatives, But Could Spread COVID-19.

Different ways to model a pandemic

Numberphile: The Coronavirus Curve. (YouTube, 22:17min) “Ben Sparks explains (and codes) the so-called SIR Model being used to predict the spread of coronavirus (COVID-19).”

I played along at home and created my own version with Geogebra, but you can also find Ben Sparks’s version here: SIR Model.

Be sure to also check out the links in the description of the video.

3Blue1Brown: Simulating an epidemic. (YouTube, 23:11min)

“While here we looked at what you might call an “agent-based” SIR model, if you want to see what it looks like as a set of differential equations, Ben Sparks just did a lovely video on the topic over at Numberphile [see above].

There are a few reasons I like the agent-based model here, for demo purposes at least. It’s a bit easier to understand for those who are not comfortable yet with ODEs, for one. It also conveys how things are not deterministic; no real-world curve will look as smooth as the differential equations. It also makes it way easier to ask questions and bake other assumptions into the model. Introducing things like travel or community centers into the differential equations would get very hairy very quickly. For those who want to go much more deeply into this, the Institute for Disease Modeling has a lot of models free for people to look at and play with.”