Today is a happy day. All regions have something positive to report.
Brazil: Both, daily cases and deaths are lower than the day before, for the second day. Daily deaths are now even trending down. This could be a trend. I certainly hope so. But let's not forget that the actual numbers are much higher than reported, especially now that the virus is moving from the coastal cities into the vast underdeveloped rain forest. Outlook: Very Bad With Hope
US minus CA,NY,WA: Both, daily cases and deaths are lower for two days in a row. Daily cases are still trending steeply upwards but you can see a peak forming and numbers might not reach 15 per 100K as feared. Daily deaths are declining more steeply now. I am cautiously happy. Outlook: Very Bad With Hope
California: Cases continue their rise, about to scrape the 15 per 100K line. Daily deaths are trending downward for the first time in days and might settle below 50 per day for real. Outlook: Bad With Hope
New York: Both trendlines are down from the day before. I would be very happy if I were wrong with my earlier predictions of daily cases settling at 3 per 100K. And it looks just like that. Daily deaths in the single digits for the second time ! Outlook: Satisfying Trending To Good
Washington: Both trendlines are down from the days before, which is a good sign. But daily cases have been trending upwards for a month now and daily positives still remain above 5%. There has been no fatality reported ! Outlook: Not Completely Bad With Hope
Germany: Daily case trend is unchanged, still pointing up for 13 days but it is obvious that a peak has been passed and, baring another huge clustered outbreak, cases should soon go along the dotted 13-day trendline. Deaths went up a little but they are still fine. Outlook: Good Trending Better
France: After three days without new numbers, they are back on track. I took out the Hopkins numbers and the daily case trend has thus come down a lot, but still pointing up. I still would not be surprised if the daily numbers were to go flat at around 0.7 per 100K but I hope that I am wrong. Deaths are in the double digits again but nothing to worry about. Outlook: Good
Tunisia: There continue to be a few daily cases and there still are only two deaths in 35 days. Europe has opened its borders to Tunisia and Tunisia has opened theirs to Germany (but not France) and I shall see and wait how increased tourism will affect the numbers. Outlook: Excellent
On getting tested and thinking that this will do any good: The Bavarian prime minister has proposed a massive testing plan for his state, which drew a lot of criticism. Here are a few facts.
The proposed test looks for the presence of viral RNA. This test can result in a false negative result (the test fails to detect the virus even though it is present) if not done properly or if the virus has travelled from the nose, where it the swab is done, to the lungs.
If you test positive, it will scare you and it will probably land you in a two-week self-quarantine. If you develop symptoms, then the test had the good effect of getting you out of traffic sooner than if you had waited for the first symptoms to arise. And as a consequence, you infected fewer people. This also applies to those many more people who test positive but will never get sick. Because these can also infect others. We just don't know how many of them. In the end, for those who test positive, testing could then lead to a reduction in virus transmission. This is good
People who test negative would get the impression that they are clean. They could then behave more carelessly, even unconsciously. In addition, if you test negative today, you could get infected tomorrow, most likely even without knowing it. In this case, a recent negative test would give you even more false security. This could lead to an increase of virus transmissions. This is bad.
Now let's put the good and bad together:
Currently, 0.2% of the German population are Covid-19 cases. They have thus tested positive for RNA. Assuming that as many as 10x more people could carry the virus without knowing it, this would still only be 2% of the population. And it is these 2% of Germans for which testing has a good effect.
On the other hand, 98% of the Germans would be negative for the virus. Administering the test to these people could have a bad effect.
We have many assumptions in these numbers and only proper statistics will be able to give definite answers – several months from now. But it is clear where my thought experiment is going: 98% bad effect outperforms the 2% good effect. Even if the good effect were much greater than the bad effect, it is likely that the good effect will never outperform the bad one. Thus, hundreds of thousands of Euros will, at best, have no effect on the curve and, at worst, even increase the number of cases.
One scenario where RNA testing could be useful is for travellers on airplanes. But only if the test result is immediate and if a positive test bars a person from boarding a plane. In all other cases it is nothing but expensive eyewash.
To make matters worse, there is also the antibody test. It is not important for this discussion because it does not tell you if you are currently infectious. But read on if you want to know more:
After infection with he virus, a person's immune system starts fighting it. As a part of this reaction, the body produces antibodies against the SARS-CoV-2 virus. Some people make a lot of antibody, others produce only very little which depends, amongst others, on how much virus was able to get into your body. Some antibodies linger for months and thus protect you from a second infection, some antibodies are gone within a few weeks and you can then get infected a second time. It takes years of research to find out every little detail about a viral infection and therefore, at this point, we can only speculate and work with assumptions. Nobody knows definitely how Coronavirus works and anybody who says so is lying.
If you test positive for the antibody, it means that you had been infected with the virus at some point in the past. It does not mean that you had been sick nor does it mean that you were able to transmit the virus to others. But the probability is high that you had infected somebody. And yes, you can still be infectious.
Knowing how many people carry the antibody is very important for the understanding of the virus. It will also tell us how many people have really been infected during all these months. These things would be very helpful to know, but I doubt that this was the prime minister's intention.