Thread by @chrischirp

THREAD on vax study for B.1.617.2 (new "Indian" variant):

@jburnmurdoch broke a story from PHE data with the first real world analysis of AZ & Pfizer vaccine efficacy against B.1.617.2.

I am less convinced this is great news than some. Here's why.
ft.com/content/a70d42… 1/16

The study estimates that both vaccines are 33% at preventing symptomatic B.1.617.2 disease after 1 dose (vs 51% against B117 ("Kent")) and 81% effective after 2 doses (vs 87% for B117).

Too little data on preventing severe disease to say much but v likely to be better. 2/16

So the vaccines do mostly work against B.1.617.2 - especially after 2 doses. That's good news - but not surprising.

We already had evidence from a care home outbreak, & Bolton hospital. Early lab studies suggested less escape than B.1351 "S Africa"
blogs.bmj.com/bmj/2021/05/18… 3/16

Govt ministers have been reassuring the public for a few weeks that vaccines would work against this vaccine - with little acknowledgement that this efficacy might be lower than against the current dominant B117 variant
standard.co.uk/news/uk/matt-h… 4/16

The fact is that while total vax escape would be terrible (& thank god we don't have it), *any* vax escape has consequences for the roadmap & current levels of opening.

Efficacy of only 33% after 1 dose *matters* when only 40% of adults & no kids have been fully vaxxed. 5/16

SAGE modelling subgroup (Spi-M) modelled the roadmap with a MORE transmissible variant but NO loss of vaccine efficacy which suggested that 50% more transmissibily could lead to a surge as bad as this winter.
assets.publishing.service.gov.uk/government/upl… 6/16

SAGE minutes from last Thursday's (13 May) meeting highlight the concern about increased transmissibilty and also the potential for *some* vaccine escape (less than "S African" variant)

assets.publishing.service.gov.uk/government/upl… 7/16

The JUNIPER subgroup for SAGE also presented evidence for increased transmissiblity of this variant last Thursday (13th May) with this warning:

"Incontrovertible evidence that B.1.617.2 is more transmissible may come too late"

assets.publishing.service.gov.uk/government/upl… 8/16

The govt decided to press on with stage 3 of roadmap on Monday 17th May anyway - although it was pretty clear from Thursday's (13 May) meeting that Test 4 of "no new variants changing risk" had been failed. 9/16

So we now have a situation where we have a more transmissible variant AND with moderate vax escape after one dose. This scenario was NOT modelled by SAGE SPI-M. But given either of these is modelled to lead to a surge, combo makes the scarier SAGE models more likely. 10/16

The scarier models are scary under just step 3 of the roadmap (where we are now) - and get considerably worse if we progress to step 4 in June.

Letting infection run also provides more opportunities for further mutation (and thousands of new long covid cases). 11/16

And yes - it might still be that the variant is not so transmissible as to cause a big problem - and some of its rapid spread may be due to this moderate vax escape (although most cases in younger unvaxxed groups).

But as JUNIPER said - risk benefit is for caution NOW. 12/16

The way out is to vaccinate - FULLY vaccinate - as many people as possible as quickly as possible. And to do this BEFORE we move to step 4 of the roadmap.

AND to augment vax with supported isolation, local contact tracing, targeted testing, safer indoor spaces. NOW. 13/16

In particular we need safer schools - where we have unprotected populations in children. We are already seeing case rates in Bolton in school-age children going through the roof.

We urgently need PHE data on B.1.617.2 spread in schools as well. 14/16

So the good news about today's story is that it confirms that FULL vaccination still provides a way out (alongside other measures).

The bad news is that it makes proceeding with current roadmap a very bad idea & moving to Step 3 last Monday might have been a big mistake. 15/16

As individuals we can also do our bit:
1) get vaccinated when it's offered (both doses!)
2) assume you can still pass it on, esp after just 1 dose, and keep being careful. 16/16