As the pandemic continues and more genomic data becomes available we are starting to see the unravelling of prior findings on the introduction and transmission of SARS-CoV-2. This statement from our article below is worth keeping in mind... 1/6 https://twitter.com/nresearchnews/status/1265319367467626497

A recent study from Mike Worobey, @LemeyLab attempt to resolve the earliest introduction of the virus in the US & Europe by accommodating unsampled 'simulated' viruses from Hubei & supports independent introductions of the infamous WA1 and Washington State outbreak clade 2/6

While in Europe the assertions that the initial outbreak in Bavaria was responsible for seeding the Italian outbreak is refuted with a more likely scenario of both the German and Italian outbreaks being independently introduced from China. https://www.biorxiv.org/content/10.1101/2020.05.21.109322v1 3/6

The previous conjecture with the Bavaria link by @trvrb was already met with skepticism https://twitter.com/trvrb/status/1235382661968879616?s=20 so not surprising that this has been now formally tested in a more rigorous fashion 4/6

As pointed out in this thread https://twitter.com/BillHanage/status/1265098558690246658?s=20 sampling matters especially early on in an outbreak when all genomes are remarkably similar. Undersampling of viruses and locations can make phylogenetic inferences highly precarious 5/6

These comments and more are all laid out in our article https://www.nature.com/articles/s41564-020-0738-5 6/6