How would a 'protect the vulnerable and let everyone else go back to normal' approach to COVID play out? I see three main scenarios, each with important consequences to consider... 1/
Scenario A: Let's suppose it's possible to identify who's at high risk of acute/chronic COVID-19. Then somehow find way to isolate these people away from rest of society for period it would take to build immunity in low risk groups and get R below 1 & infections low... 2/
This would mean isolating at least 20% of UK population (if use over 65 as age cutoff) and this period of isolation could be several months (or longer if rest of population continues to be cautious, reducing the overall rate of infection and hence accumulation of immunity). 3/
Scenario B: Identify risk groups & reduce infection among their contacts to very low levels through testing & isolation. Because risk groups so embedded within society, this may well end up suppressing transmission (i.e. won't generate much immunity): 4/
Scenario C: Don't fully isolate risk groups away from rest of society or put substantial infection-preventing restrictions on their contacts. Accept the high level of severe disease that likely will result as a consequence of this choice. 5/
If scenario A or B aren't feasible, the default of a 'go back to normal' approach will be scenario C. Need to discuss possible options for response to COVID, but also need to think through implications and have honest acknowledgement of what consequences could be. 6/6

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Adam Kucharski

Adam Kucharski Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @AdamJKucharski

6 Oct
If COVID cases/hospitalisations/deaths are rising - as they are in many European countries - there are only two ways the trend will reverse.... 1/
A. Enough change in control measures and/or behaviour to push R below 1. The extent of restrictions required will depend on population structure/household composition etc. But given existing measures are disruptive and R is above 1, could take a lot of effort to get R down. 2/
B. Accumulation of sufficient immunity to push R below 1. However, evidence from Spain (e.g. bbc.co.uk/news/world-eur…) suggests ICUs will start hitting capacity before this point, so to avoid them being overwhelmed, would likely end up cycling between epidemics and (A) above. 3/3
Read 4 tweets
4 Oct
I often see the misconception that control measures directly scale COVID case numbers (e.g. “hospitalisations are low so measures should be relaxed”). But in reality, measures scale *transmission* and transmission in turn influences cases. Why is this distinction important? 1/
If discussions are framed around the assumption of a simple inverse relationship between control and cases, it can lead to erroneous claims that if cases/hospitalisations are low, control measures can be relaxed and case counts will simply plateau at some higher level. 2/
But of course, this isn’t how infectious diseases work. If control measures are relaxed so that R is above 1, we’d expect cases - and hospitalisations - to continue to grow and grow until something changes (e.g. control reintroduced, behaviour shifts, immunity accumulated). 3/
Read 6 tweets
24 Sep
COVID app launches today. Would encourage everyone to download & use - we need every tool we can get to tackle this pandemic, and effectiveness will increase dramatically with number of users. Plus there are couple of features I hope could be particularly powerful...1/
First, streamlining venue registration could make it much easier to link people to settings of common exposure, helping notify people associated with superspreading events: 2/
Second, the app could help pick up contacts that would otherwise be hard to trace (i.e. causal contacts outside home/work/school) - we estimated that these are the contacts that can really hinder effectiveness of test & trace: thelancet.com/journals/lanin… 3/
Read 4 tweets
21 Sep
As well as limits on gathering size in recent months ( ), another feature of Sweden that stands out is household size - it's smallest average in Europe, with majority single occupant (ec.europa.eu/eurostat/web/p…). What effect could this have on transmission? 1/
The estimated risk of transmission per contact is higher within household than outside household (thelancet.com/journals/lanin…). This means it can be helpful to think of an epidemic as a series of within-household outbreaks, linked by between household transmission... 2/
If the average size of an outbreak in a household is H, and each infected person within a household spreads infection to C other households in community on average, then we can think of the 'household' reproduction number as equivalent to H x C. 3/
Read 6 tweets
20 Sep
I'm seeing more and more suggestions that groups at low risk of COVID-19 should go back to normal while high risk groups are protected. What would the logical implications of this be? 1/
First, let's pick an example definition of risk. If we use infection fatality risk alone for simplicity (which of course isn't only measure of severity), there is a clear age pattern, which rises above ~0.1% around age 50 and above ~1% around age 70 (medrxiv.org/content/10.110…) 2/
Suppose hypothetically we define the over 65 age group as 'high risk'. That's about 18% of the UK population, and doesn't include others with health conditions that put them at more at risk of severe COVID. 3/
Read 13 tweets
19 Sep
Spain reported 239 COVID deaths yesterday & France 154. So seems odd for this model to predict that if UK continues on same trajectory, then adds some not-particularly-good TTI in 8 weeks, deaths will peak at ~50 per day (unless I've misunderstood plot...)
I presume model is based on this recent paper, which predicted a second peak at ~30 deaths per day (medrxiv.org/content/10.110…). For context, there were 27 COVID deaths reported in UK yesterday: coronavirus.data.gov.uk/deaths
Quick clarification (thanks for flagging @marbin2050): the report of 239 deaths in Spain was from a day earlier (english.elpais.com/society/2020-0…) – 162 were reported yesterday (english.elpais.com/society/2020-0…)
Read 4 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!