Read on Twitter
There are *so* many things wrong with this, starting with the implicit suggestion that an individual paper in @TheLancet carries particular merit greater than the body of scientific work as a whole. But evolutionarily it is nonsensical. Let me explain 1/n https://twitter.com/MLevitt_NP2013/status/1307504237048406019
Things do not inevitably become less virulent over time, it depends on a lot of things including the connection between transmission and virulence, and the availability of new hosts 2/n
If being more virulent leads to more transmission, then that will be selected! The only brake on this will be if so many potential hosts are sick/dead that there's no-one to transmit to - which depends on host contacts rather than the virus 3/n
Another thing is that in a rapidly growing population, you get selection for things that grow *fast*. If you transmit to 10 but it takes a month, won't matter if your competitor transmits to 2 in a couple days. Relevant in a growing epidemic (and is a well known result) 4/n
The original tweet refers to 'natural weakening' er... 5/n
First the only 'natural' way 'weakening' would happen is adaptation, and how would we expect a lockdown to impact that? Well if contacts happen less frequently, and those with symptoms isolate, the virus would need to adapt to a longer, less symptomatic course of infection 6/n
I don't want to drive this into a discussion of the evolution of virulence; although I enjoy teaching it and have previous https://www.pnas.org/content/104/44/17441/tab-article-info 7/n
That field has more theory than results, as @mlipsitch commented early in the pandemic - instead of thinking we are clever by talking evolution (remember evolution is cleverer than you are), we should show we are clever by the way we act against the pandemic 8/n
What do we know about this virus and transmission? Well a lot takes place before symptoms. In other words, transmission and virulence are sort of decoupled. In which case... there's no benefit to reduced virulence 9/n
It's also silly to get het up about mutation making it more dangerous (you don't believe me, check @edwardcholmes (who knows more about this than me or indeed most) https://www.nytimes.com/2020/09/11/opinion/coronavirus-mutation-reinfection.html 10/n
But *this* is the most damning observation about the original ridiculous assertion - the mutation supposedly weakening the virus went extinct. Technically speaking, extinction is not selectively advantageous https://twitter.com/CT_Bergstrom/status/1307610925768216576?s=20 11/n
Throughout the pandemic, there have been folks who seize on anything they can to minimize it and its consequences. I don't understand their motives but I confess I do find it very very frustrating 12/n
I'd *love* an informed discussion about pandemic management, including ways to move forward that prioritize the things that matter to us most such as schools, and which recognize all age groups are not equally at risk 13/n
But stuff which pretends everything is OK and there are no hard choices to be made does not help. It's worse than unhelpful. It provides fuel to those channeling misinformation and risking lives. And will end up making the pandemic worse, not better 14/end
