Even before the first cases of COVID-19 In Europe, at the end of January 2020, signs were already circulating on social media that something strange was happening.
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A study led by researchers from the IMT School for Advanced Studies in Lucca (Italy) and published this week Scientific Reports has identified clues of growing concern over pneumonia cases in messages posted on Twitter in seven european countries (France, Germany, Italy, the Netherlands, Poland, Spain and the United Kingdom) between the end of 2019 and the beginning of 2020.
Analysis of the tweets shows that the “whistle-blowing” came precisely from the geographic regions of Europe where the first outbreaks later developed.
To conduct the research, the authors first created a single database with all messages posted on Twitter that contained the keyword ‘pneumonia” in the seven most widely spoken languages of the European Union (English, German, French, Italian, Spanish, Polish and Dutch) from December 2014 to March 1, 2020.
The word ‘pneumonia’ was chosen because this disease is the most serious condition induced by SARS-CoV-2, and also because the 2020 flu season was milder than previous ones, so there was no reason to think it was responsible. of all the mentions and concerns.
Subsequently, the authors carried out a series of adjustments and corrections in the messages of the database to avoid overestimating the number of tweets that mentioned pneumonia between December 2019 and January 2020, that is, in the weeks between the WHO announcement indicating that the first “cases of pneumonia of etiology unknown “had been identified (on December 31, 2019) and the official recognition of COVID-19 as a serious communicable disease (on January 21, 2020).
In particular, all tweets and retweets that contained links to virus news were removed from the database to exclude from the count the media coverage of the emerging pandemic.
Increase in tweets about ‘pneumonia’ in January 2020
The results show an increase in tweets mentioning the keyword ‘pneumonia’ in most of the European countries in the study as early as January 2020, indicating growing concern and public interest in cases with the disease.
In ItalyFor example, where the first containment measures to contain COVID-19 infections were introduced on February 22, 2020, the rate of increase in mentions of pneumonia during the first weeks of last year differs substantially from the rate observed in the same weeks of 2019.
That is, potentially hidden sources of infection were identified several weeks before the announcement of the first local source of a COVID-19 infection, on February 20 in Codogno (Italy). France showed a similar pattern, while Spain, Poland and the United Kingdom experienced a two-week delay.
The authors also geolocated more than 13,000 pneumonia-related tweets in this same period and found that they came exactly from territories where the first cases of infections would later be reported, such as the Lombardy region in Italy, Madrid in Spain, and the Paris region. in France.
Also alerts of ‘dry cough’
Following the same procedure used for ‘pneumonia’, the team also produced a new dataset with the keyword ‘dry cough‘, another of the symptoms later associated with COVID-19. They also observed the same pattern, with an abnormal and statistically significant increase in the number of mentions of the word during the weeks leading up to the increase in infections in February 2020.
“Our study adds to the existing evidence that social networks can be a useful epidemiological surveillance tool. They can help to intercept the first signs of a new disease, before it proliferates undetected, and also track its spread”, highlights Massimo Riccaboni, Professor of Economics at the IMT School who have coordinated the research.
According to the authors, this is especially clear in a pandemic situation like the current one, when failure to identify early warning signs left many national governments blind to the unprecedented scale of the looming health crisis.
In a successive phase of the pandemic, social media monitoring could help public health authorities to mitigate the risks of a regrowth of contagion, for example, adopting stricter measures of social distancing where infections seem to increase, or vice versa, relaxing them in other areas.
These tools could also pave the way towards an integrated system of epidemiological surveillance managed globally by international health organizations, the researchers conclude.