Thread by @federicolois

1/ Our preprint with @LDjaparidze is online at @medrxivpreprint
"SARS-CoV-2 waves in Europe: A 2-stratum SEIRS model solution"
medrxiv.org/content/10.110…

2/ We extended the SEIRS model to support stratified isolation levels for healthy <60 and vulnerable individuals.

3/ We forced the model to predict daily deaths curves and the reported age serology ratio for key metropolitan areas in Europe. The immunity level estimations obtained were: Madrid 43%; Catalonia 24%; Brussels 73%; and Stockholm 65%.

4/ We predict that, with the exception of Brussels, no location can return to normal life without having a second wave (albeit in Stockholm a smaller one). Those predictions are more sensitive to population, population over 60, and the reported deaths than to the IFR.

5/ For locations far from the herd immunity threshold (HIT) we searched what isolation values allow to return to normal life in 90 days while minimizing final deaths. Shockingly all isolation values for healthy <60 were negative. (i.e. coronavirus parties)

6/ Assuming an ideal 1-day long vaccination campaign with a 77% efficacy vaccine, we compared predicted final deaths of those 90-day strategies for all possible vaccination dates against a 180-day long vaccine waiting strategy with mandatory isolations.

7/ We found that mandatory isolations (i.e. schools and workplaces closed) produces more final deaths if the vaccination date is later than (Madrid: March 7 2021; Catalonia: Dec 26 2020; Paris: Jan 12 2021; London: Jan 25 2021)

8/ Secondary findings suggested by the model include: 15% of SARS-CoV-2 deaths are 'with' the virus; Very low infectiousness period may be the cause of deaths curves valleys after lockdowns; An early wave of a competing variant could explain the low death rates in Asia.

9/ Finally, we propose that the probability of covid-19 disease-related damages suffered and caused by a single individual choosing NOT to completely isolate should be used to cover those risks.

10/ If some virus is so contagious and so damaging to a large proportion of the population that the disease-related damages risks can not be covered, then that virus pretty much will be the end of normal life. SARS-CoV-2 is not.

11/ You can play with simulator that we built to analyze this at sars2seir.com/paper-09-2020/

12/ If the Brussels prediction looks wrong in retrospect is because Belgium does something others don't. They include possible cases in their death series... Are you serious Belgium?😡

https://twitter.com/federicolois/status/1328702427902652416

At sars2seir.com shows you can look at both series.

13/ As you can see, when we remove the suspected cases (as we do in every other country) this is the proper behavior to expect. A clear second wave for Brussels too.