What Arguments on Vaccinations Run through YouTube Videos in Italy? A Content Analysis

"In the light of the fact that the number of videos on vaccination is high and the number of viewers is growing, it is important to monitor the web to understand audience characteristics, what and who influences public opinions and in which way; in other terms, to understand the dynamics of vaccine criticism so as to design and use more effective dissemination strategies."

In recent years in Italy, there has been a gradual decrease in vaccination coverage. More than half of Italian regions do not meet the 95% coverage rate for paediatric immunisation programmes set by the Ministry of Health. The Italian situation is characterised by significant differences in immunisation policies among regions arising also from conflicting opinions on mandatory vaccination. The influence of the internet on vaccination-related decisions is well documented. The aim of the current research is thus to examine the content of Italian YouTube videos related to paediatric vaccinations in general and to understand the potential of messages in influencing public awareness and opinions. In a context where there is a will, at the national level, to move from compulsory to voluntary immunisation, web monitoring could be important in guiding immunisation policies.

An observational study was conducted that involved searching for YouTube videos in September 2015, with an update in January 2016, by using the keyword "vaccinations". This led to selection of 123 recently posted videos in Italian on child vaccination (2014-2015). Videos were classified according to the message tone.

Pro-vaccination videos were 62 (50%), anti-vaccination were 28 (23%), and neutral or without a clear position in favour of or against vaccination were 33 (27%). Focusing on the first 2 groups, pro-vaccination videos had a higher number of views compared with those unfavourable (p < 0.001). However, anti-vaccination videos were liked more by viewers than positive ones (p < 0.001) in addition to being more frequently shared (p < 0.001).

This aspect was confirmed and particularly evident when analysing the time trend of videos according to message tone. The time trend of selected videos showed that the month when the largest number of videos was published is the same as that shown by the Google trend for the word "vaccine" - i.e., December 2014 - meaning that the web search on vaccines was particularly intensive during that period. In that period, there was a large debate about the safety of Fluad flu vaccine due to some deaths in the elderly population that was vaccinated. In the same way, the other spike pertains to April 2015, during World Immunization Week 2015 (24-30 April). Although it is not possible to attribute with certainty web searches to a specific event, it is worth noting that despite the fact that positive videos outnumbered negative ones in both periods, the negative videos were significantly more liked and shared than all the other ones.

Overall, positive videos were mainly developed by health professionals (44%) as compared with other videos. "Non-health professional" sources, such as forums, news, television, individuals, anti-vaccine and other associations, were characterised mainly by negative (75%) and neutral/ambiguous videos (91%) (p = 0.002). "Non-health professional" or "consumer" videos had a higher number of average likes, dislikes, and comments than "health professional" videos, though the differences were not statistically significant (p > 0.05).

Negative videos were significantly longer than positive ones, and they dealt mainly with general rather than specific vaccinations. This could mean that anti-vaccination videos need more time to be argued, and the idea of risk is related to vaccination in general.

Fear appeal to persuade people about health behaviours is a controversial issue. Content analysis revealed that the argument mostly present both in positive (52%) and negative (71%) videos was fear appeal, related to the side effects or toxicity of adjuvants in vaccines, on one hand, and fear of the possible negative consequences of a natural communicable disease, on the other hand. Out of 26 videos where only fear appeal occurred, 22 (85%) were produced by non-health professionals. As the researchers argue, beyond coercive approaches and increased education, it is crucial to create a trusting relationship with a healthcare provider responsible for providing clear information about vaccination risks and benefits. This "ideal" situation can be threatened by the web, which allows people to search for health information while bypassing the healthcare professional.

In conclusion, most of the videos were positive in tone, but those that disapproved of immunisation were the most liked and shared. Lay users seem to pay more attention to such videos, perhaps because they generate more debate. Future research could focus more on the actors who publish vaccine-critical content and the strategies they use to mobilise the population. From the perspective of communication advocacy actions, the researchers suggest that public health institutions and scientific societies should not only be more present on the web by exploiting new web channels, but they need to become skilled "influencers", which means to capture a significant amount of attention in social media conversation so as to disseminate more effectively accurate and credible information regarding vaccination at the individual, community, and society level. So, these findings encourage putting more effort into implementing interventions that include new healthcare communication web tools.