Last year I read the WHO’s initial report on the covid-19 outbreak, which gave early warnings on the nature of covid and laid out specific steps to prevent it from becoming a pandemic. Only a handful of countries followed the recommendations, leading to our present situation.
Now the WHO has published another report sharing the results of their investigation into the origins of covid. I’ve read the read the report and summarized it below – although being much longer and with fewer surprises I skimmed much of it.
Population-scale data shows no evidence of covid in Wuhan prior to mid-January 2020, at which point there is a sudden increase in several indicators. This is consistent with the sharp increase in confirmed cases of covid around mid-January.
Retrospective analysis of medical records and biological samples discovered no new cases of covid prior to 2020 January. (None of the illnesses examined were consistent and the samples were all negative, except a few samples for which were too small to test.) Of course, some cases of covid may have left no records, and mild cases might have been filtered out in the retrospective search without careful analysis. Many early cases were connected to the Huanan market, some were connected to other markets, and for a significant number no known connection could be established.
The earliest known case continues to be 2019 December 8 (onset) and was laboratory-confirmed. The first known family cluster was from 2019 December 26. There are 174 known cases of covid in Wuhan in 2019 December, most of which are laboratory-confirmed.
The report mentions but has no comment on studies claiming that covid was circulating in other countries variously 2019 Sept - Dec. I have read some of these studies for myself and I continue to believe these are exceptionally unlikely to be true positives.
The outbreak in Wuhan preceded the outbreak in the other parts of Hubei province.
Genomic etc. analysis suggested that the most recent common ancestor of the early Wuhan cases of covid to be sequenced is 2019 December 11, with a stddev of several weeks. A wide variety of studies give various dates for the MRCA in November or December.
The report is highly confident that laboratory escape is not involved in the origin of covid.
Contaminated frozen goods have caused several outbreaks of covid in regions with no community transmission of covid. The report speculates that frozen goods may have played a role in the initial outbreak of covid, but does not find significant evidence in favor of that theory.
On the basis of genomic comparisons, it is highly probable that sars-cov-2 passed through intermediate animal hosts between bats and humans, although there was little evidence to help identify exactly which species were involved. Direct transmission from bats is still a possibility.
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