Tuesday, February 11, 2020

COVID-19: should we be worried? Yes

Dr Neil Ferguson of Imperial college seems the go-to guy:
"Our estimates – while subject to much uncertainty due to the limited data currently available – suggest that the impact of the unfolding epidemic may be comparable to the major influenza pandemics of the 20th century,” he said. [Daily Telegraph].
I heard him on PM yesterday evening. He reckons 60-70% of the UK population will eventually get it, of whom 1% will die; big error bars for the next three weeks. Given asymptomatic transmission with R0 2-3 it can't be kept out or contained within the UK over any extended period. Especially when it goes exponential in countries outside of China.

From Le Monde: (Practise your French) :
"selon une modélisation, un groupe de trois Etats se situe dans le trio de tête des pays les plus menacés par une arrivée du virus : l’Egypte, l’Algérie et l’Afrique du Sud. Ils sont suivis d’un second groupe constitué, lui, du Nigeria et de l’Ethiopie."
Lots of links between China and Africa. Public health screening and treatment not brilliant in the latter.

UK risks: (i) breakdowns in the supply chain May/June when the pandemic really takes hold here; (ii) personal incapacity and/or need to self-quarantine.

What can you do? 

- Shop now for cans of soup, long-life milk, dried fruits and cereals, sanitary items; face-masks (they won't look so ridiculous soon).

- Check out your camping cooker.

- Petrol in the car - don't forget the car can charge mobile phones.

Buy stuff you'll be able to consume after the pandemic so you're not wasting money.

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The Mormons famously have a survivalist level of supplies, c. six months. But 2-4 weeks should do it - you can always go half-rations.

I always think the best time to panic-buy is before other people realise they have to.

Note

Best estimate of case doubling time at present seems to be 7 days. If, by the end of February, there were 16 invisible cases in the UK, time to one million is (sixteen doublings) = 16 weeks = four months.

It won't seem a major problem here before Easter is my prediction (note big error bars!).

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Update (13/2/20): I today cancelled our June holiday in Crete. The call-centre operative seemed unsurprised when I mentioned COVID-19. We have, however, been hit by a stinging cancellation fee, the entire deposit, 20% of the overall cost.

I'm thinking this summer is going to be disastrous for the holiday companies and for travel insurers.

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Update: If you have a VPN into the UK it is educational to watch this:
"Hannah Fry leads a nationwide experiment to help plan for the next deadly flu pandemic, which could happen at any time. How many will it kill? What can we do about it?"
The BBC/Cambridge model parameters are basically spot-on for Covid-19 (R0=1.8; lethality=2%).

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Update (14/2/20): My brother wrote to me and observed:
"I would take issue with one of your precautions: Don’t waste time and (increasingly large amounts of) money on surgical (or most other types of) masks. Even the better ones have an interweave gap some three times larger than the virus and invariably get damp, increasing the stickability.

Leave your eyes, nose and mouth open to the world, just don’t touch them without washing/gelling hands (as frequently as possible)."
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8 comments:

  1. Wikipedia gives 1.5 < R_0 < 3.9 so the middle value here is 2.7 (+- 1.2) This agrees with the Ferguson transmissibility estimate of 2.6. Most similar to the 1918 Influenza rate, its modern form as H1N1 caused the 2009 pandemic and infected 20% of all humanity with an R_0 = 1.75 apparently.

    From the Ferguson report I get that after infection onset you have 22 days after which you are either dead or recovered.

    I still have some cans left over from the Brexit panics of late last year.

    On a different matter if you listen to (a repeat of) todays "Life Scientific" you will learn about the future career of a member of STL.

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    Replies
    1. I note that you don't really commit to being worried...

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    2. Actually I am not sure whether you mean "worried about the virus" or "worried about the pandemic". On the latter panic buying hasn't started here yet, but at the first sign I will top up (building on a reserve on unused Brexit panic cans); on the former I await to see what really happens in the UK.

      Factors like the weather (cold March versus spring-like March) could yet have an impact on its UK spread ability, if this is also Influenza-like.

      Of course it could always mutate....

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    3. I read somewhere that, unlike the flu, this virus is unlikely to be impeded by the warm weather. The only advantage to a summer outbreak-peak in the UK is that the NHS will be relatively deloaded.

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  2. The data coming out of China is very noisy. Proximate cause of death is not always reported as Covid-19. Plus they probably ran out of testing kits in many areas. The "levelling out" of the number of infections is therefore probably a reporting artefact. The virus will still see an infinite potential host set at this early stage, even in China, so it will still be in its exponential phase.

    It seems at an optimal point for spreading so will struggle to mutate to an even more virulent form. It may have some scope to increase its own transmissability, amp-up R0. Or it could hijack more of its host's resources for self-replication thereby enhancing its lethality. But it's doing OK (by its own lights) at the moment.

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  3. Admittedly I was surprised to hear this morning on the radio news that the figures for new infections in China was down 20% following earlier reductions.

    Maybe it is effective measures kicking in, maybe it is some local authorities not reporting properly, or maybe they have just run out of testing kits.

    As you say it is just too early to tell.

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  4. [Re: update 13th] Seems a bit unfair over 3 months early to have a stinging cancellation charge. I know of some with a booking to Vietnam for Easter, but I can guess your advice on that.

    The fact that the Chinese authorities have been messing about with the figures yesterday, leads to the question as to how many more "recalculations" will come.

    One alternative might be to go on a cruise with the proviso that all passengers will be quarantined in their cabin for the entire voyage.

    Otherwise it is a "self-quarantining holiday" this summer!

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  5. My personal doubling model seemed to match the BBC4 "Pandemic" repeat's much more sophisticated mathematical model pretty well...

    https://www.bbc.co.uk/programmes/p059y0p1. Vietnam might still be OK at Easter...

    ReplyDelete

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