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Martin Juhl Profile picture
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24 Jan, 14 tweets, 6 min read
Quick thread on recent data regarding

➡️ Herd Immunity Threshold (HIT)
➡️ Immunity induced by infection
➡️ Case story from Manaus, Brazil
➡️ Immunity from vaccination
1/x
Here are a list of places with a total of 40-76% infected:
Manaus (76%)
Mumbai (75%)
indiatoday.in/coronavirus-ou……
Iquitos (71%), Ecuador (45%), Karachi (~40%), Ischgl (~40%), & NYC (40%)
2/x
Manaus, Brazil was thought to have hit 76% of all had been infected in spring

Science Paper: "Three-quarters attack rate of SARS-CoV-2 in the Brazilian Amazon during a largely unmitigated epidemic"
3/x
 science.sciencemag.org/content/371/65… Image
Furthermore, here is a more extensive collection of data showing percentage infected in specific areas in the range of 29-98%
4/x
Data on immunity after infection have so far indicated a solid immune response, and lasting immunity for at least 8 months (anticipated on avg to last longer, there are just not data further out yet)
5/x
Odds ratio = 0.17 for all reinfections compared with PCR confirmed primary infections (83% protection). Avg 160d to reinfection
Symptomatic cases supported by pos PCR results, previous infection reduced the odds of reinfection by at least 90% (OR 0.06)
6/x
 bmj.com/content/372/bm…
FT article on the BMJ NHS study above
7/x
 amp.ft.com/content/929ef3…
Thus, with a supposedly strong immune response to infection, it is a bit concerning that Manaus ( is again seeing a surge similar to the previous first wave, which was estimated to have resulted in 76% total infected.
8/x

Image
Average age of Manaus is much lower than for example São Paulo or much European countries (only 6% above 60). IFR from first wave was already 0.28% with a young population. technologyreview.com/2020/09/22/100…
9/x Image
Speculation, that it is based on new P.1 variant, but currently based on limited data (13/31 pos PCR test samples collected in Manaus between Dec 15-23), but “Everything points to this variant being behind the way the pandemic is evolving in Manaus"
10/x
 mobile.reuters.com/article/amp/id…
Potentially, the vaccines provide slight better protection compared to a previous infection, although this is also based on small numbers
11/x
Pfizer/BioNTech vaccine data on variant B.1.1.7:

“These data, together with the combined immunity involving humoral and cellular effectors induced by this vaccine, make it unlikely that the B.1.1.7 lineage will escape BNT162b2-mediated protection”
12/x
 biorxiv.org/content/10.110…
Follow-up #1
Moderna vaccine neutralize B.1.1.7, while 6x weaker against B.1.351
Follow-up #2
B.1.351 lineage (a.k.a. 20c/501y.v2) also seems to partially escape neutralization of previously infected individuals serum samples biorxiv.org/content/10.110…

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More from @MartinJuhl2

Martin Juhl Profile picture
26 Jan
Comparing the Covid-19 deaths to influenza deaths in Sweden

Sweden have had between 300-1100 flu deaths per year since 2015
1/x Image
Sweden now have 11,247 Covid-19 deaths and around 15% infected

Covid-19 is thus already 10x worse than the worst flu season in recent years (2017-18) and 37x worse than the mildest (2015-16)
Graph
@Marco_Piani

2/x Image
Sweden’s current Population Fatality Rate (PFR) for Covid-19 is >0.1%, while for influenza it has been 0.010-0.0029%
3/x
Other countries
Read 4 tweets
Martin Juhl Profile picture
26 Jan
Compilation on recent assessments from various sources using different models to provide an early estimates on relative and current reproductive number & transmissibility of the new B.1.1.7 Variant of Concern
1/x
@Peter_R_Hansen B.1.1.7 relative reproductive number ≈ 1.43 times larger. (generation time 4.7) thus 43% more infectious

Estimation for 1 day = 1.08 [CI 1.07-1.09] (8% pr day)

Estimation for 7 days 1.71
2/x
@SSI_dk @henrik_ullum
Cluster B.1.1.7 is clearly more contagious:
Increased relative reproductive number
SSI 1.2-1.5
3/x
Read 10 tweets
Martin Juhl Profile picture
26 Jan
New Danish study out comparing quick tests to PCR tests

Better late than never, but really wished this had been done earlier (back in October 2020)

➡️12th October


➡️17th October


➡️5th November
The overall sensitivity and specificity of the antigen test were 69.7% and 99.5%, the positive and negative predictive values were 87.0% and 98.5%. Ct values were significantly higher among individuals with false negative antigen tests compared to true pos medrxiv.org/content/10.110…
Results very much in line with what was shared here 5th November.
Antigen quick tests have the benefit of speed, which is very important contact tracing and isolation and can help keep society more open and well as and easy way to protect the elderly ImageImageImageImage
Read 5 tweets
Martin Juhl Profile picture
25 Jan
Currently, some positive signs coming out of Israel.

Although, If one compared to other countries, which are also in lockdown, cases are dropping at same rate, therefore a bit early to separate lockdown vs vaccination effect
1/6 Image
No decline in seven-day rolling average of new deaths (per 100k) yet
2/6 Image
But, If one zooms in on the 60+ vaccinated population & compare to the subsection that was vaccinated just before Christmas (4wks ago) a significant vaccine effect in relation to hospitalization is observed (see caveats tweet)
3/6
 dailymail.co.uk/news/article-9…

Image
Read 6 tweets
Martin Juhl Profile picture
3 Jan
Hvad ville der være sket, eller hvad vil ske, hvis vi mister kontrollen med smitten i DK

Dette er baseret på følgende

➡️Hvor mange vil blive smittet
➡️Ekstrapolering fra nuværende tal
➡️Brug af aldersjusterede dødelighed
➡️Læringer fra udlandet

1/x
R0 værdien (hvor mange 1 smittet, smitter videre) for SARS-CoV-2, er estimeret til 2,5

Man skal minimum op på 60% samlet set, dette kan godt ske i flere bølger. Hænger sammen med årstid & restriktioner

thelancet.com/pdfs/journals/…

Flokimmunitet = 1 - 1/R0
For SARS-CoV-2 = 60%
2/x
Den spanske syge, influenza pandemien i 1918-1919, kom i tre bølger.

Det menes i følge bogen "The Great Influenza", at den første bølge var en mildere form, og efter mutation og "passage" gennem flere personer, blev mere dødelig

3/x
Read 19 tweets
Martin Juhl Profile picture
3 Jan
Collection of input to the discussion on:
➡️Two doses 3-4 weeks apart (per protocol)
vs
➡️Delay 2nd dose of up to 3 months

As with everything regarding this pandemic, there are no easy solutions, only difficult compromises.
1/x
 @henrik_ullum @Heunicke @stinuslindgreen
Pfizer/BioBTech Protocol here

2nd dose is provided after 21 days & readout was 7 days after 2nd dose
pfe-pfizercom-d8-prod.s3.amazonaws.com/2020-09/C45910…
2/x
Moderna dosing & schedule

The Moderna COVID-19 Vaccine is administered intramuscularly as a series of two doses (0.5
mL each) 1 month apart

fda.gov/media/144637/d…
3/x
Read 13 tweets

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