The PHE risk assessment of Delta/B.1.617.2/'India' has been updated today, 3 June.

- *new* INFECTION SEVERITY risk assessed as RED (with Iow confidence)
- VACCINES risk still assessed as RED but now with HIGH confidence.

Previous versions linked below.

A thread.
TRANSMISSIBILITY BETWEEN HUMANS
RED risk
HIGH confidence

"Transmissibility appears greater than wild type (first wave) SARS-CoV-2Delta continues to demonstrate a substantially increased growth rate compared to Alpha, across multiple analyses. ...
"... Delta cases are rising whilst Alpha cases are declining. Secondary attack rates, including household secondary attack rates, are higher for Delta, but these are not yet corrected for vaccination status. There is in vitro evidence suggestive of increased replication in ...
"biological systems that model human airway. It is highly likely that Delta is significantly more transmissible than Alpha.
INFECTION SEVERITY
RED risk (newly quantified in this report)
LOW confidence
"Increased severity (hospitalisation risk) when compared to AlphaEarly evidence from England and Scotland suggests there may be an increased risk of hospitalisation compared to contemporaneous Alpha ...
"cases. A large number of cases are still within the follow up period. In some areas, hospital admissions show early signs of increasing, but the national trend is not clear.
IMMUNITY AFTER NATURAL INFECTION
AMBER risk
LOW confidence
"Experimental evidence of functional evasion of natural immunity but insufficient epidemiological dataPseudovirus and live virus neutralisation using convalescent sera from first wave and Alpha infections shows a ...
"reduction in neutralisation. National reinfection surveillance data are being analysed. There is no increase in numbers of reinfections in the SIREN national healthcare worker cohort.
VACCINES
RED risk
HIGH confidence (was moderate confidence last week)
"Epidemiological and laboratory evidence of reduced vaccine effectiveness There are now analyses from England and Scotland supporting a reduction in vaccine effectiveness for Delta compared to Alpha. ...
"This is more pronounced after one dose (absolute reduction in vaccine effectiveness against symptomatic infection of approximately 15-20% after 1 dose). Iterated analysis continues to show vaccine effectiveness against Delta is higher after 2 doses but that there is a ...
"reduction for Delta compared to Alpha. There is a high level of uncertainty around the magnitude of the change in vaccine effectiveness after 2 doses of Oxford-AstraZeneca vaccine. Although this is observational data subject to some biases ...
", it holds true across several analytic approaches and the same effect is seen in both English and Scottish data. It is strongly supported by pseudovirus and live virus neutralisation data from multiple laboratories. There are no data on whether prevention of transmission ...
"is affected and insufficient data to assess vaccine effectiveness against severe disease. The acquisition of an additional mutation which may be antigenically significant in a small number of cases is noted.
OVERALL ASSESSMENT
"Delta is predominant and all analyses find that it has avery substantial growth advantage.The observed high growth rate is most likely to be due to a combination of place based context, transmissibility and immune escape. Both English and Scottish analyses
"continue to support the finding of reduced vaccine effectiveness which has increased to high confidence. New early data from England and Scotland suggest a possible increased risk of hospitalisation compared to Alpha. The priority investigations are vaccine effectiveness
"against hospitalisation and transmission, household secondary attack rate corrected for vaccination, characterisation of the generation time, viral load and period of infectivity, and epidemiological studies of reinfections.
Quotes above from the PHE Risk Assessment for Delta/B.1.617.2/'India' published 3 June 2021.
The 'Nepal variant' story sounds, at first though, to be a distraction from the analysis that Delta/B.1.617.2/'India' variant is now classified as having red (high) risk in:
- transmissibility
- infection severity
- vaccines.

We need another Number 10 Press Conference.

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More from @Dr_D_Robertson

3 Jun
Cumulative case numbers for variants published by PHE today, 3 June.

I think we all get the picture now that the Delta/B.1.617.2/'India' variant is becoming dominant.

Here are the charts.

And a final tweet linking to today's risk assessment of Delta, which isn't great news.
Logarithmic cumulative chart.
Heatmaps of weekly cases
Read 7 tweets
3 Jun
What is the 'Nepal Variant'?

This is the Transport Secretary's statement just now, justifying why Portugal has moved from the green list of countries.

"a sort of Nepal mutation of the so-called Indian variant which has been detected"
This was featured prominently in today's Daily Mail.
The World Health Organization apparently do not know about it.

Read 7 tweets
3 Jun
The green/amber/red list and the role of the Joint Biosecurity Centre in those risk analyses.

Reminiscent of the JBC work on the CONTAIN framework for deciding which local authorities should be in which tiers.

A short thread.
The JBC is responsible for publishing a risk assessment that is used to determine which countries are on the green, amber, and red lists.

gov.uk/government/spe…
We can *assume* that these risk assessments have been conducted and have informed the reported move of Portugal from the green list to the amber list.

Here is how we are told they are completed

gov.uk/government/pub…
Read 10 tweets
1 Jun
The Government's strategy has always been that, on repoening, cases would increase.

A short thread.
Cases are, indeed, increasing.

There appears to be an approximate constant rate of increase.

However, testing is very much dependent on who is tested and where testing is taking place, surge testing and the like.
The Government's Roadmap has depended on four tests.

None of these tests involve cases (directly).

Read 17 tweets
1 Jun
On the WHO naming (a short thread with some comments on the new naming system.

1. Here it is. Good that it's here but it's far too late
who.int/en/activities/…
2. any scientist would have thought about using the Greek alphabet (because that's what scientists do) but probably discounted it because, well, it's a bit.. Greek (see point 1)
3. it's not future-proof.

10 Greek letters have been used up already out of 24. It's back to the drawing board for variant 25 (or at least another decision has to be made as to which e.g. alphabet to use)
Read 8 tweets
27 May
PHE have published their data for Variants of Concern to 26 May2021

- B.1.617.2 is becoming dominant with 3,535 new cases
- But also increases in these variants of concern
P1 (+21)
B.1.351 (+32)
- New variant under investigation C.36.3 (+109)

cumulative chart excl B.1.1.7
Cumulative chart excluding B.1.1.7 and B.1.617.2

Over 900 cumulative cases of B.1.351 (South Africa)
Cumulative chart on an exponential chart
Read 15 tweets

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