Thread by @firefoxx66

*Very* surprised to hear this from @ECDC_EU & @EASA this morning. Our work on #SARSCoV2 20A.EU1 shows this variant spread incredibly effectively across Europe due to travel & now accounts for significant proportion of seqs circulating in many countries.

euronews.com/2020/12/03/cov…

While the variant initially spread from Spain, phylogenetic data shows that it also transmitted onward from secondary European countries.

Though we haven't studied other variants in as much detail, I have no doubt we'll find similar stories of travel-associated introductions.

Our work suggests that indeed, 'honour-based' quarantine alone may not be the ideal policy. But we suggest this because it doesn't seem to have worked as well in practice as one might have hoped - not because travellers posed no risk of introducing #SARSCoV2 (to the contrary).

You can check out our recently-updated preprint on #SARSCoV2 #COVID19 20A.EU1 here:

And I hope to provide even more updated stats on 20A.EU1 and many other variants later today.

medrxiv.org/content/10.110…

The risk of travellers isn't static & won't be the same everywhere: if a country has a large local epidemic, travellers may not pose a greater threat. But, when countries have worked hard to get to low cases, I believe our work shows that yes, travellers can be a very real risk.

Important to update: The full ECDC report has more nuance in quarantine & testing guidelines reflecting that different strategies are needed at different times & between different countries. It's a shame this doesn't come through in the EC but it is reassuring!