Thread by @firefoxx66

1/ A mini-view at how globally #SARSCoV2 #COVID19 was spreading in March:

In early Mar, 2 mutations arose (4002T, 13536T - yellow), seemingly in Europe. About month later, despite rolling lockdowns, it was on 6 continents.

2/ To be crystal clear: there's no reason to think these mutations are special at all - they just allow us to follow what happened to a variant seemingly from Europe during a period when Europe was starting to shut-down.

The same thing was happening to many other variants.

3/ You've probably heard scientist say that #COVID19 #SARSCoV2 was spreading in countries before we even knew it was there. We can illustrate the explosive spread across Europe & Asia from 13 Feb - 13 Apr with another cluster nearby (mut 313T)

4/ It's worth keeping in mind that sampling during these early days is sparse for many countries, as well - these variants could have been in more countries & we might just not have samples.

5/ These clusters don't really tell us anything we don't already know - but I think they illustrate strikingly just how quickly #COVID19 #SARSCoV2 spread in those early days.

It's worth keeping in mind as we start opening & travelling again.

6/ A return to 'full normal' will let #COVID19 #SARSCoV2 take off - just like it did then.

We know a lot more now, so we can be a lot safer - but we must always remember that SARS-CoV-2 is more wide-spread than we 'know'. In a way, every positive test is playing catch-up.

7/ If you'd like to take a look at these two cluster yourself, you can find them highlighted in yellow here (4002):
nextstrain.org/ncov/europe?c=…

and here (313): nextstrain.org/ncov/europe?c=…

8/ In an upcoming narrative I'll be exploring some of the Swiss sequences in these & other clusters! Keep an eye out :)