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Let's talk about #Herd_Immunity, given some recent interviews on the #COVID19SWEDEN strategy have talked about this being 'a result'... is this achievable, sensible and acceptable?
1. #Immunity: Do people get long term #Immunity? We can't possibly know yet! But a study from China found that not all those who recovered from #COVID19 had high levels of antibodies... https://www.medrxiv.org/content/10.1101/2020.03.30.20047365v1
2. #Immunity: Looking to other coronaviruses, a study on #SARS patients found approx. 50% did not have SARS specific IgG (an antibody) 3 years after infection... and we don't tend to have long term immunity to the common cold either... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/
3. Re-infection: are we seeing re-infections? In S. Korea, so far 111 people have tested positive following negative tests, leading to a hypothesis of "re-activation"... A LOT more data + research is needed! https://www.reuters.com/article/us-health-coronavirus-southkorea/south-korea-reports-recovered-coronavirus-patients-testing-positive-again-idUSKCN21S15X
http://www.koreaherald.com/view.php?ud=20200412000213&np=3&mp=1
https://www.medrxiv.org/content/10.1101/2020.03.26.20044222v1.full.pdf
http://www.koreaherald.com/view.php?ud=20200412000213&np=3&mp=1
https://www.medrxiv.org/content/10.1101/2020.03.26.20044222v1.full.pdf
4. Long term morbidity: there are clinical reports that #COVID19 causes damage to heart, liver, and kidney... as well as lungs. We currently don't have data on the long term health impacts of the acute infection (or treatments). https://nymag.com/intelligencer/2020/04/more-bad-news-on-the-long-term-effects-of-the-coronavirus.html
5. Numbers infected: the formula used to determine how many need to be vaccinated to reach #Herd_Immunity is (assuming 100% efficacy):
1 - 1/R0
R0 = 1.5
33%
R0 = 2 50%
R0 = 2.560%
R0 = 3 67%
R0 = 3.5 71%
https://www.ecdc.europa.eu/sites/default/files/documents/RRA-seventh-update-Outbreak-of-coronavirus-disease-COVID-19.pdf
1 - 1/R0
R0 = 1.5
33% R0 = 2
50% R0 = 2.5
60%R0 = 3
67%R0 = 3.5
71% https://www.ecdc.europa.eu/sites/default/files/documents/RRA-seventh-update-Outbreak-of-coronavirus-disease-COVID-19.pdf
6. Lets take scenarios of R0 = 2 and 3.5. In #Sweden, this means 5.1 - 7.2 million infections.
Using IFRs of 0.1 - 1% means between 5100-72000 deaths. An IFR estimate from China was 0.66%, and unpublished from Germany of 0.37%
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30243-7/fulltext https://www.nature.com/articles/d41591-020-00011-3
Using IFRs of 0.1 - 1% means between 5100-72000 deaths. An IFR estimate from China was 0.66%, and unpublished from Germany of 0.37%
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30243-7/fulltext https://www.nature.com/articles/d41591-020-00011-3
7. #Vaccine: There are currently 115 #COVID19 #Vaccine candidates, most still at early stages. However, 90% don't make it usually... so we cannot be sure a vaccine will happen, or when it would happen. https://www.nature.com/articles/d41573-020-00073-5
8. #Treatment: @WHO currently reports 137 studies for different #COVID19 therapeutics 
. And some 960 clinical trials on-going.... I mean, that's impressive (but obvs same caution as 
).
https://app.powerbi.com/view?r=eyJrIjoiNjQxZWZhOTItYzU1ZS00Y2QxLWE1ODAtOTViZjhmNjEyZjNiIiwidCI6ImY2MTBjMGI3LWJkMjQtNGIzOS04MTBiLTNkYzI4MGFmYjU5MCIsImMiOjh9 https://app.powerbi.com/view?r=eyJrIjoiMjA1ZDA0N2YtOTUzMi00ZTU1LWFlMDAtMjFlMTVkN2U2ODQyIiwidCI6ImY2MTBjMGI3LWJkMjQtNGIzOS04MTBiLTNkYzI4MGFmYjU5MCIsImMiOjh9
. And some 960 clinical trials on-going.... I mean, that's impressive (but obvs same caution as ). https://app.powerbi.com/view?r=eyJrIjoiNjQxZWZhOTItYzU1ZS00Y2QxLWE1ODAtOTViZjhmNjEyZjNiIiwidCI6ImY2MTBjMGI3LWJkMjQtNGIzOS04MTBiLTNkYzI4MGFmYjU5MCIsImMiOjh9 https://app.powerbi.com/view?r=eyJrIjoiMjA1ZDA0N2YtOTUzMi00ZTU1LWFlMDAtMjFlMTVkN2U2ODQyIiwidCI6ImY2MTBjMGI3LWJkMjQtNGIzOS04MTBiLTNkYzI4MGFmYjU5MCIsImMiOjh9
9. #Immunity, #R0, #IFR, #Reinfection, #Vaccine, #Treatment are all uncertain and the data presented often preliminary or single site studies. But, given the above, is a #Herd_Immunity approach acceptable to YOU?
