Background. Recently, In Italythe vaccination coverage for key immunizations , as MMR , has been declining , with measles outbreaks . In 2017, the Italian Government expanded the number of mandatory immunizations establishing penalties for families of unvaccinated children . During the 2018  elections campaign, immunization policy entered the political debate , with the government accusing oppositions of fuelling vaccine scepticism. A new government established in 2018 temporarily relaxed penalties and announced the introduction of flexibility . Objectives and Methods. By a sentiment analysis on tweets posted in Italian during 2018, we aimed at (i) characterising the temporal flow of communication on vaccines, (ii) evaluating the usefulness of Twitter data for estimating vaccination parameters, and (iii) investigating whether the ambiguous political communication might have originated disorientation among the public. Results. The population appeared to be mostly composed by serial tweeters tweeting about everything including vaccines. Tweets favourable to vaccination accounted for 75\% of retained tweets, undecided for 14\% and unfavourablefor 11\% . Twitter activity of the Italian public health institutions was negligible. After smoothing the temporal pattern, an up-and-down trend in the favourable proportion emerged, synchronized with the switch between governments, providing clear evidence of disorientation  . Conclusion. The reported evidence of disorientation documents that critical health topics, as immunization, should never be used for political consensus. This is especially true given the increasing role of online social media as information source, which might yield to social pressures eventually harmful for vaccine uptake, and is worsened by the lack of institutional presence on Twitter . This calls for efforts to contrast misinformation and the ensuing spread of hesitancy.
Background. In Italy, in recent years, vaccination coverage for key immunizations as MMR has been declining to worryingly low levels . In 2017, the Italian Gov't expanded the number of mandatory immunizations introducing penalties to unvaccinated children's families . During the 2018 general elections campaign, immunization policy entered the political debate with the Gov't in charge blaming oppositions for fuelling vaccine scepticism. A new Gov't established in 2018 temporarily relaxed penalties . Objectives and Methods. Using a sentiment analysis on tweets posted in Italian during 2018, we aimed to: (i) characterize the temporal flow of vaccines communication on Twitter (ii) evaluate the polarity of vaccination opinions and usefulness of Twitter data to estimate vaccination parameters, and (iii) investigate whether the contrasting announcements at the highest political level might have originated disorientation amongst the Italian public. Results. Vaccine-relevant tweeters interactions peaked in response to main political events. Out of retained tweets, 70.0\% resulted favourable to vaccination, 16.5\% unfavourable, and 13.6\% undecided, respectively. The smoothed time series of polarity proportions exhibit frequent large changes in the favourable proportion , enhanced by an up and down trend synchronized with the switch between gov't suggesting evidence of disorientation among the public . Conclusion. The reported evidence of disorientation documents that critical immunization topics, should never be used for political consensus. This is especially true given the increasing role of online social media as information source, which might yield to social pressures eventually harmful for vaccine uptake, and is worsened by the lack of institutional presence on Twitter , calling for efforts to contrast misinformation and the ensuing spread of hesitancy.
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Recently, In Italythe
In Italy, in recent years,
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, as MMR ,
as MMR
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, with measles outbreaks
to worryingly low levels
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Government
Gov't
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establishing penalties for families of unvaccinated children
introducing penalties to unvaccinated children's families
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general
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, with the government accusing oppositions of
with the Gov't in charge blaming oppositions for
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government
Gov't
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and announced the introduction of flexibility
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By
Using
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at
to:
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characterising
characterize
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communication on vaccines,
vaccines communication on Twitter
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evaluating the
evaluate the polarity of vaccination opinions and
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for estimating
to estimate
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investigating whether the ambiguous political communication
investigate whether the contrasting announcements at the highest political level
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among the
amongst the Italian
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The population appeared to be mostly composed by serial tweeters tweeting about everything including vaccines. Tweets favourable to vaccination accounted for 75\%
Vaccine-relevant tweeters interactions peaked in response to main political events. Out
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undecided for 14\% and unfavourablefor 11\% . Twitter activity of the Italian public health institutions was negligible. After smoothing the temporal pattern, an up-and-down trend
70.0\% resulted favourable to vaccination, 16.5\% unfavourable, and 13.6\% undecided, respectively. The smoothed time series of polarity proportions exhibit frequent large changes
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emerged,
, enhanced by an up and down trend
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governments, providing clear
gov't suggesting
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among the public
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health topics, as immunization,
immunization topics,
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. This calls
, calling