.@alisonannyoung has been one among the most active, persistent, and fair-minded reporters covering lab accidents in the US @USATODAY. This long piece makes the serious case for investigating poss lab origin for #SARSCoV2. usatoday.com/in-depth/opini….
This is not about conspiracy theories or China-bashing. This is about the basic principle, at least as old as Rev. Bayes and Sherlock Holmes, that when something unusual happens, you have to consider explanations that are also individually unlikely.
To be explicit, the @WHO mission's conclusion that a lab accident was unlikely was unjustified (as @alisonannyoung notes they are frequent) but even if true, global pandemics are also uncommon, so by definition the sequence of events leading to one do not happen all the time.
Many responses to this from various perspectives. I don't claim a lab accident is the most likely, only that it is a candidate among others with enough plausibility to need investigating.
Several responses including from @arambaut whose views on all such topics I hold in the highest regard emphasized the lack of evidence that the virus was ever in WIV.
If the @WHO mission report documents that 1) there is system at WIV such that no virus is handled in the lab without being sequenced; 2) no sequence plausibly ancestral to SARS-CoV-2 was recorded; and 3) the records examined were complete, then lab hypothesis wd be less likely.
Happy to be corrected but 1 is implausible because wild samples containing many viruses not explicitly studied were handled there and could have infected a worker subclinically. 2 seems true from my limited understanding. 3 seems not true from what I've read.
Note that in many western countries including the Netherlands cmr.asm.org/content/21/3/4… and the US journals.sagepub.com/doi/10.1177/15…, and the UK theguardian.com/science/2014/d…, lab accidents are not routinely made public and are shrouded in various levels of secrecy.
Asking if there may have been an accident in Wuhan is _not_ equivalent to asserting a conspiracy, among other reasons because a lab worker contaminated by a bat sample and asymptomatically transmitting to others is one possible scenario, in which case perhaps no one would know.
Again, not saying this or any other scenario happened, but that the WHO's public statements to date provide little reason to change one's priors one way or the other. That may be where we end up, as there may not be conclusive evidence.
But without citing more detailed evidence, WHO mission's conclusion means either they had a 0 prior on lab accident which is unaffected by evidence, or they have evidence they haven't yet made public, or they are overinterpreting the evidence they have made public.

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More from @mlipsitch

15 Mar
CONGRATULATIONS DR. @AccorsiEmma defending her PhD with flying colors today. Thanks especially to @chuttenh who supervised much of the work linking microbiome and #epidemiology #EpiTwitter and to committee members @SHaneuse and @BillHanage @HarvardEpi @CCDD_HSPH @HarvardChanSPH
Two of her thesis papers have been published. genomebiology.biomedcentral.com/articles/10.11…
Read 4 tweets
28 Feb
New preprint on estimating and Interpreting vaccine efficacy trial results for infection and transmission | medRxiv. With ⁦@rebeccajk13⁩. Long discussion on applications to observational VE studies medrxiv.org/content/10.110…
tl;dr: Analyze separately cases ascertained for different reasons. Don't combine those found because symptomatic with those found by screening a cross section or by testing contacts.
In an RCT there are typically one of these (symptomatic cases, the primary endpoint in most COVID trials) or two (symptomatics and cross-sections). Symptomatics are incident cases and VE is properly measured by 1- incidence rate ratio. The VE measured is vs symptomatic infxn
Read 18 tweets
25 Feb
Our paper on identifying and mitigating biases in epidemiologic studies of #COVID-19 is now out and is #OA . doi.org/10.1007/s10654…. Skillfully led by
this project involved much of our group and many discussions arising from papers we were reading.
including @XuetingQ @EvaRumpler @LeeKShaffer @rebeccajk13 Ed Goldstein @NeneRiehus from @CCDD_HSPH with special guests @mats_julius and @mugecevik .
We consider the challenges of several kinds of studies: 1. Seroprevalence studies to estimate cumulative incidence
where a key challenge is representativeness of participants
Read 17 tweets
25 Feb
@ZoeMcLaren Thanks for tweeting about this article. I'm going to leave the matching issue for another day, but I want to add a note of caution as one of the authors. We did not claim, and the data do not directly address, the reduction in total infections.
@ZoeMcLaren We used the word "documented infection" to highlight the fact that many infections may have gone undocumented, especially those not symptomatic. The documented infections is a mixture of symptomatic (probably most of them) and asymptomatic (probably a smaller fraction)
@ZoeMcLaren As a consequence, it is mathematically possible to have a big effect on documented infections but a smaller effect on total infections. As an extreme case (likely more extreme than the truth) suppose that symptomatic infections are detected with probability 90% and
Read 6 tweets
31 Jan
@profshanecrotty Thanks @profshanecrotty for another super informative thread (ht @HelenBranswell for tweeting). My 2 cents is just to remember that the comparison between sero+ and sero- in the control arm in Novavax was not randomized and involved ~40 cases in each group.
@profshanecrotty @HelenBranswell Study was of course not designed to assess natural immunity, so kudos to the scientists for reporting these important data, but caution in interpretation. Several reasons to expect bias in observational seroprotection studies like this dash.harvard.edu/handle/1/37366…
@profshanecrotty @HelenBranswell In particular, those who got infected before (sero+) are likely still at high risk for subsequent infection(due to job, housing, use of transport, other persistent factors), leading to noncausal positive association betwn prior and future infection (confounding).
Read 4 tweets
31 Jan
Reupping this. Existing vaccines may well have been unable to get us to the herd immunity threshold before the variants made things harder. Now more unlikely. But if we can identify (hard) and vaccinate (harder) the most vulnerable it will make continued spread less destructive.
I haven't double-checked @roby_bhatt 's numbers but there is evidence so far that the vaccines are highly effective against the most severe forms of COVID, even in South Africa where most cases were the local variant.
Read 4 tweets

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