COVID-19 might have started as early as August 2019, according to a research study by Harvard University. The study's results were reportedly dismissed by China, and its methodology challenged by independent scientists as well.

The study, according to a report by BBC News, has not undergone peer review, and is based on satellite imagery of movement and traffic around Wuhan hospitals. Moreover, it reportedly conducted a trace of internet-based studies for particular medical symptoms.

The research indicated a noticeable increase in vehicles parked outside the city's six hospitals between the latter part of August until early-December last year.

At the same time, Harvard said in its report, that "this coincided with an increase in online searches" for possible symptoms of COVID-19 such as "diarrhea and cough."

The BBC news site reported that this is a significant result since the earliest COVID-19 case reported in Wuhan was not until the start of December 2019.

Online Search Trends Disputed

The Harvard study stated that, while they cannot confirm whether the increased volume of searches for covid-related symptoms was directly related to COVID-19, their evidence backs other recent studies that show the occurrence took place before it was traced back to the "Huanan Seafood market."

While the research claims though there was a rise in online searches for COVID-19 symptoms, specifically "diarrhea," on the popular Chinese search engine Baidu, officials at the Chinese firm said, "There was in fact, a drop in searches for 'diarrhea'" during that period.

Reports said the term "diarrhoea" which Harvard University used in the paper is, in fact, translated from the Chinese language as 'symptoms of diarrhoea'."

According to BBC News, it checked on the tool of Baidu that allows online users to analyze the search queries' popularity, like "Google Trends." As a result, "symptom of diarrhoea" as a search-term, indeed showed a rise in queries from August last year.

However, the news agency said that when it ran the word "diarrhoea," a popular search-term in Wuhan, in contrast, it presented a drop from August 2019 until the onset of the pandemic.

'Diarrhoea' a Search-Term Best Match for Confirmed COVID-19 Cases

Benjamin Radar, the Harvard Paper's lead author, said the search-term they had selected for "diarrhoea" was chosen as "it was the best match for confirmed COVID-19 cases" and was suggested as a search-term related to the deadly virus.

Moreover, he said, they also looked at the search popularity for two other common COVID-19 symptoms -- "fever" and "difficulty in breathing" and there was a slight increase in searches for the term "fever" after August akin to the rate of the term, "cough." Meanwhile, queries for the term, "Difficulty in breathing" also dropped after the same month.

Questions on the use of "diarrhoea" as a gauge or indicator of the illness have also been raised. 

Specifically, a comprehensive UK research of almost 17,000 COVID-19 patients found that the term "diarrhoea" was found to be the "7th most common symptom," which, the research said, was way below the Top 3 COVID-19 symptoms of cough, fever and shortness of breath.

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