I wrote yesterday about the spread of the UK B117 variant based on data up to the 13th Dec warning that it could become dominant across much of the UK & across most age groups. Recent data released up to end of Dec now suggests that this has already happened. Short thread. https://twitter.com/dgurdasani1/status/1344774555718590464

Recent data from LSHTM shows that the B117 is either dominant, or very close to dominant in most regions with rapid increases being seen all across England. No region appears to have been spared, and it's very nearly out-competed the usual strain completely in SE England.

This means that we will continue to see increases within the next few weeks in other parts of England, where it will likely completely replace the previous strain as it has in much of SE England. This is very bad news- because it makes the spread much harder to contain.

It also shows the rapidity with which spread occurs geographically, and the difficulty in containing this, even with restrictions in place. An important lesson for countries which have identified cases or imports and are trying to contain this. Aggressive & fast action needed.

Without this, these strains are likely to get established very quickly, with the consequences of increased transmissibility, and increased R numbers, making the pandemic very hard to contain regionally & globally.

Unfortunately, as expected although the variant appears to have first become dominant among <20 yr olds, more recent data suggests spread to older age groups, where it is now similarly dominant, although still less dominant in over 70s still. https://twitter.com/_nickdavies/status/1345119880010457088?s=20

We are now clearly in the position where this variant will replace the previous one within a few weeks, which means that R is likely to increase even further than currently. Movement to older age groups will be felt in terms of rising cases, hospitalisations & deaths soon.

We're already too late on this, and our window to contain spread regionally & within age groups has unfortunately passed. But the situation is going to get worse, given current trends across England. We need an urgent strict national lockdown right now & schools going remote.

Unfortunately between 20-25,000 deaths in January are already baked in, given most of those who will die in the next 3-4 weeks have already been infected. But if we don't act now, we'll see many more in February, and the real risk that the NHS will not be able to treat everyone.

This may further increase fatality rates. And R number will continue to rise until the variant completely replaces the previous viral strain across England. This means the doubling rate of cases will continue to fall over the coming week, with much faster spread.

We're in a very difficult position now. The Imperial study suggests that even with lockdown, although the growth of the variant reduced, it didn't reverse (R remained above 1). It will be very difficult to contain this without very strict measures in place.

This means that unless we really commit to a strict & robust strategy to contain this, we're in for mass death - not just from COVID-19 but also from other diseases as NHS services are overwhelmed. We need a clear plan from govt *now*. A policy of half-way measures won't work.

Link to the paper can be found here:
https://cmmid.github.io/topics/covid19/reports/uk-novel-variant/2020_12_31_Transmissibility_and_severity_of_VOC_202012_01_in_England_update_1.pdf

Sorry just want to say in the earlier tweet, that as R increases, doubling *time* will fall, not doubling rate. Thanks @BorisBarbour for pointing out this error.