Evidence of Distrust and Disorientation towards Immunization on Online Social Media after Contrasting Political Communication on Vaccines. Results from an Analysis of Twitter Data in Italy.

Samantha Ajovalasit , University of Catania
Veronica Dorgali, University of Florence
Angelo Mazza
Piero Manfredi, Università di Pisa

Abstract Background. In Italy in recent years, vaccination coverage for key immunizations, as MMR, showed a worrying decline resulting in large measles outbreaks. As a response in 2017, the Government expanded the number of mandatory immunizations and introduced penalties for families of unvaccinated children. With the upcoming 2018 general elections, immunization policy entered the political debate, with the government accusing oppositions of fuelling vaccine skepticism. The new government established in 2018 temporarily relaxed penalties, and announced the will to introduce forms of flexibility. Objectives and Methods. By a sentiment analysis on tweets posted in Italian during 2018, we attempted at (i) characterising the temporal flow of communication on vaccines over Twitter, (ii) evaluating the usefulness of Twitter data for estimating vaccination parameters, and (iii) investigating whether the prolonged epoch of contrasting announcements at the highest political level might have originated disorientation amongst the public. Results. Tweets favourable to vaccination accounted for 75% of retained tweets, undecided for 14% and unfavourable for 11%. After smoothing, a very clear yearly up-and-down trend in the favourable proportion emerged, well synchronized with the switch between governments, providing evidence of distrust. Conclusions. The identified evidence of distrust on vaccination shows that critical health topics should never be used as tools for political consensus, especially given the increasing role of online social media as a source of information. This is reinforced in Italy by the lack of institutional presence on Twitter, a fact calling for efforts to contrast misinformation and the ensuing further spread of hesitancy.

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 Presented in Session 83. Health and Wellbeing in a Digital World