There have been criticisms of a study of the United States suggesting that the coronavirus might have been present in the chinese city of Wuhan from August of last year.
The study of Harvard University, who has been the subject of a well publicised at its release earlier this month, has been rejected by China and has seen its methodology is contested by independent scientists.
That is what the research said?
The research, which has not been the subject of a peer review, is based on satellite imagery of the movements of traffic around hospitals of Wuhan and the follow-up research online to find symptoms specific medical.
It indicates that there has been a significant increase in the number of vehicles that are stationed outside of the six hospitals of the city of the end of August to the 1st of December 2019.
This coincided, says the Harvard report, with an increase in research for the possible symptoms of the coronavirus, such as “cough” and ” diarrhoea “.
This would be an important conclusion because the first reported case in Wuhan was not until the beginning of December.
The academics write : “Although we cannot confirm if the increase in volume was directly related to the new virus, our data support other recent work showing that the emergence occurred prior to the identification to the seafood market of Huanan. ”
The study from Harvard has gained a lot of traction in the media, with the president Trump, who has been very critical of the response to pandemic China, tweeting an article by Fox News highlighting the findings of the researchers. The tweet has been viewed more than three million times.
Then, is it that their evidence stand ?
The study states that there was an increase in requests online for the symptoms of the coronavirus, especially the ” diarrhea “, on the popular chinese search engine Baidu.
However, officials of the company Baidu have challenged their conclusions, saying that there was in fact a decrease in searches for “diarrhea” during this period.
So, what is happening ?
The term used in the article of Harvard University is reflected in the fact the chinese as a ” symptom of diarrhea.”
We have verified this on the tool in Baidu that allows users to analyze the popularity of search queries, such as Google Trends.
The search term “symptoms of diarrhea” in fact shows an increase in queries from August 2019.
However, we also ran the term ” diarrhea “, a search term more common at Wuhan, and he actually showed a decrease from August of 2019 until the beginning of the epidemic.
A principal author of the journal of the Harvard Benjamin Rader told the BBC that “e search term that we have chosen for the “diarrhoea” was chosen because it was the best match for confirmed cases of Covide-19 and has been suggested as a search term related to the coronavirus.
We also looked at the popularity of searches for “fever” and ” difficulty breathing “, two other common symptoms of the coronavirus.
The research of “fever” have increased a little after the month of August at a similar pace to that of the “cough” and applications of “difficulty breathing” have decreased during the same period.
Questions have also been raised about the use of diarrhea by the study as an indicator of the disease.
A large-scale study conducted in the United Kingdom with nearly 17 000 patients with coronavirus revealed that diarrhea was the seventh most common symptom, well below the first three : cough, fever and shortness of breath.
What is the number of cars?
In the six hospitals, the study from Harvard reported an increase in the number of cars in the parking lots of the hospitals from August to December 2019.
However, we found serious shortcomings in their analysis.
The report indicates that the images with the cover of the trees and the shadows of the building have been excluded to avoid the overrun or under-counting vehicles.
However, the satellite images released to the media show of large areas of car parks, hospitals blocked by large buildings, which means that it is not possible to assess with precision the number of cars present.
In the tweet below, we have annotated with white boxes with the areas obscured by the tall buildings.
The angle of the pictures shown in the @ABC report on this block parts of the parking space that ternirait the data used to suggest a trend in the cars present in the parking spaces of the hospital. H/T to @Fang__z first to highlight this. pic.twitter.com/odtCflBOt8
— Benjamin Strick (@BenDoBrown) June 12, 2020
There is also an underground car park at the hospital Tianyou, which is visible on the view function of the street Itself, but only the entrance is in view of satellite imagery – not the cars under the ground.
One of the authors of the study, Benjamin Rader said: “We certainly can’t explain the underground parking garage in any period of the study, and this is one of the limitations of this type of research. ”
There are also concerns about the choice of hospitals for the study.
Hubei Women and Children’s hospital is one of the sites included, but children will rarely have need hospital treatment for the coronavirus. In response, the authors say that their results would show even greater use of parking in the whole, even if this hospital were to be excluded from the survey.
The researchers have also been able to compare their data with hospitals in other chinese cities, to see if the increase in traffic and search queries were specific to Wuhan, is where the epidemic has been revealed for the first time.
Without this comparison, in addition to the questions we have raised about online searches for medical symptoms, the evidence for residents of Wuhan receiving treatment for the coronavirus of August of last year remains highly questionable.
There are, however, still a lot that we don’t know about the spread early viruses in Wuhan.
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