In a recent article on the New York Times, the Five Stars Movement (M5S) has been accused of having caused the recent increase in measles cases in Italy. Although M5S’s politicians have repeatedly criticized the obligatory use of vaccines, it is hard to test whether the reduction in the share of vaccinated children is due to M5S’ propaganda.
The graph below, indeed, shows a negative correlation (-0.33) between the vaccination coverage for measles (at the regional level) and votes for the M5S at the last European elections (in 2014). The correlation is even more negative, when considering separately Northern and Southern regions (-0.51 and -0.47). In other words, in areas where citizens are more likely to vote for the M5S, the coverage of vaccinated children decreases.
Nevertheless, correlation is not causation. On the one hand, the success of the M5S might have increased skepticism towards vaccinations; on the other hand, citizens in areas more skeptical towards vaccinations might have supported the M5S. However, we can at least exclude the existence of pre-trends as in the period of 2005-2010 – preceding the electoral success of the M5S – we do not see any change in the vaccinations coverage across Italy (see graph below).
Overall, voting for the M5S appears related to skepticism towards vaccinations. We do not know yet whether M5S's politicians are directly responsible for the recent measles' increase or if they are just dangerously capitalizing political support by exploiting this delicate matter.