1) A Danish study @TheLancet has followed over 520 000 people, from the 1st to 2nd surge.

Similar to some other studies, they find that those with a prior #SARSCoV2 infection had ~80% lower risk of #reinfection, but only ~47% reduced in those ≥65 yrs
thelancet.com/journals/lance… Image
2) The @TheLancet article describes how Denmark during tested ~0.5 M people for #SARSCoV2 during wave 1.

At the end of 2020, ~10% of the population tested every week.

In all of 2020, Denmark tested ~4 million people (68% of their pop.) and 64% of those had been tested >1 time.
3) In their analysis, they also included an alternative cohort, that looked at individuals throughout the pandemic (& not only those testing positive in the 1st & 2nd wave), thus examining reinfection risk in a group of 2.4 M people, of which 28 875 had been previously infected.
4) In this alternative cohort, they also found a similar reduced reinfection risk (by ~79%; 95%CI 74·9–82·1), and no one infected >2 times.

Similar protection from reinfection also seen in frequently tested #healthcare & social workers (~15.600 individuals) – ~81% risk reduction
5) They were unable to correlate symptoms with the degree of protection. Potential bias could be due to less willingness for previously infected individuals to be tested again (thinking they are protected), resulting in overestimated protection.
6) It is also possible that those with prior infection engage in more risky behavior, which could then lead their risk exposure to be different compared with a previously non-infected individual.
7) The (sensitivity/added) analysis in routinely tested #healthcare workers was to confirm that the reinfection risk was not driven by altered testing behavior in previously infected individuals – as mentioned above, the risk was not much different, suggesting lack of such bias.
8) The authors mention that their study material covers a period when the more transmissible variants of SARS-CoV-2 were not yet established in #Denmark – these may alter reinfection risk per case, but also due to higher community transmission (i.e. higher overall exposure)
9) The risk of reinfection does however not seem to be increased from B.1.1.7:
10) The lower protection from reinfection in older individuals seems somewhat different from another much smaller study: in UK care home residents (n=103) & staff (n=106), protection from reinfection was overall ~96%, but again this is a small study.
eurosurveillance.org/content/10.280… Image
11) There are as mentioned above other studies that have reported a similar level of protection from reinfection, after a previous infection with SARS-CoV-2:

12) The authors of the new @TheLancet study highlight that their findings mean older individuals need e.g. to get effective vaccines, and that "vaccination of previously infected individuals should be done because natural protection cannot be relied on"

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More from @JCedernaes

19 Mar
Not possible to review yet, so very preliminary:

German researchers seem to claim that in some individuals - that is, in very few as reported elsewhere - the Astrazeneca vaccine may activate platelets (which regulate clotting)
The upside is that they seem to think they know how to treat these rare complications:

"The discovery means that targeted treatment can be offered to those who suffer similar clotting, using a very common medication."

3) Some more details regarding the possibility of the rare clotting/bleeding complications following the Astrazeneca vaccine, and how to possibly treat the more serious type of them:

Read 8 tweets
18 Mar
"“Our scientific position is that this vaccine is a safe and effective option to protect citizens against COVID-19,” said the head of the EMA, Emer Cooke.

She added: “If it were me, I would be vaccinated tomorrow.”"

2) However, the EMA “cannot rule out definitively a link” between the rare types of blood clots and the vaccine.

They are therefore recommending to add a description that such cases have been reported, to the vaccine leaflets, to make health workers and patients aware of this.
3) Note however that this would be a very rare event, 37 or slightly more out of 17 M recipients, bringing the reported ratio to ~ the reported rate of anaphylaxis for Pfizer & Moderna (2.5-4.7 per 1 million doses) - just from a numbers comparison.
Read 5 tweets
18 Mar
Three scientific feats of ex vivo [organ] development

1) @WeizmannScience researchers are able to keep mouse embryos alive in a bottle for half of the normal in utero development

2) An array of papers that attempt producing human blastocysts from pluripotent cells, including from fibroblasts (the type of cell often used to make induced pluripotent stem cells).

May be important for learning about development
3) Tear gland organoids that could produce tear fluid ("cry"), engineered in a dish. This could potentially in the future be useful for treating conditions such as Sjögren's syndrome, where tear production is severely lacking.

The gene Pax6 seems critical
Read 4 tweets
3 Dec 20
Lovande: En ny analys av vaccindata från #Moderna (#mRNA1273) i @NEJM finner att nivåerna av #antikroppar hos de vaccinerade deltagarna ligger kvar på höga nivåer hos samtliga deltagare ~3 månader efter att bägge vaccindoser har givits.


De fann neutraliserande antikroppar hos samtliga deltagare dag 119 (dvs. ~3 månader efter andra dosen; doserna ges med 28 dagars mellanrum).

Analyserna tyder på något lägre nivåer av neutraliserande antikroppar hos de äldre (56-70 & ≥71 år) jämfört med yngre (18-55)

Vid denna tidpunkt var också antikroppssvaret bättre än de som sågs hos individer som återhämtat sig efter en naturlig COVID-19-infektion (konvalescenssera), och som undersökts betydligt tidigare (~34 dagar) efter sin motsvarande exponering (dvs. efter en COVID-19-diagnos)

Read 11 tweets
3 Dec 20
Dödligheten (IFR) i COVID-19 med data för 45 länder, samt jämförelser med influensan – en (lång) tråd

I @nature publicerades för en månad sen en omfattande analys av infection fatality rate (#IFR), utifrån data från 45 länder & 22 antikroppsstudier.

De beräknar även infektionsmönstret i de analyserade länderna. Studien finner att IFR är lägst i åldern 5-9 (0.001%), för att gå upp till 8.29% hos de som är ≥80 år (se Fig. 1A, kom ihåg det är en log-linjär skala).

Notera att studien är accepterad men ej editerad ännu.

Många västländer hamnar på IFR 0.6-0.8%. I snitt hade 5% av invånarna i de undersökta länderna smittats fram till 1:a september i år (med en högre siffra för Latinamerikanska länder; utifrån seroprevalensdata).

Read 41 tweets

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