Tracking Public Attitudes Toward COVID-19 Vaccination on Tweets in Canada: Using Aspect-Based Sentiment Analysis

Abstract

Background The development and approval of COVID-19 vaccines have generated optimism for the end of the COVID-19 pandemic and a return to normalcy. However, vaccine hesitancy, often fueled by misinformation, poses a major barrier to achieving herd immunity. Objective We aim to investigate Twitter users’ attitudes toward COVID-19 vaccination in Canada after vaccine rollout. Methods We applied a weakly supervised aspect-based sentiment analysis (ABSA) technique, which involves the human-in-the-loop system, on COVID-19 vaccination–related tweets in Canada. Automatically generated aspect and opinion terms were manually corrected by public health experts to ensure the accuracy of the terms and make them more domain-specific. Then, based on these manually corrected terms, the system inferred sentiments toward the aspects. We observed sentiments toward key aspects related to COVID-19 vaccination, and investigated how sentiments toward “vaccination” changed over time. In addition, we analyzed the most retweeted or liked tweets by observing most frequent nouns and sentiments toward key aspects. Results After applying the ABSA system, we obtained 170 aspect terms (eg, “immunity” and “pfizer”) and 6775 opinion terms (eg, “trustworthy” for the positive sentiment and “jeopardize” for the negative sentiment). While manually verifying or editing these terms, our public health experts selected 20 key aspects related to COVID-19 vaccination for analysis. The sentiment analysis results for the 20 key aspects revealed negative sentiments related to “vaccine distribution,” “side effects,” “allergy,” “reactions,” and “anti-vaxxer,” and positive sentiments related to “vaccine campaign,” “vaccine candidates,” and “immune response.” These results indicate that the Twitter users express concerns about the safety of vaccines but still consider vaccines as the option to end the pandemic. In addition, compared to the sentiment of the remaining tweets, the most retweeted or liked tweets showed more positive sentiment overall toward key aspects (P<.001), especially vaccines (P<.001) and vaccination (P=.009). Further investigation of the most retweeted or liked tweets revealed two opposing trends in Twitter users who showed negative sentiments toward vaccines: the “anti-vaxxer” population that used negative sentiments as a means to discourage vaccination and the “Covid Zero” population that used negative sentiments to encourage vaccinations while critiquing the public health response. Conclusions Our study examined public sentiments toward COVID-19 vaccination on tweets over an extended period in Canada. Our findings could inform public health agencies to design and implement interventions to promote vaccination.

Cross-National Vaccine Concerns and Predictors of Vaccine Hesitancy in Not-Fully Vaccinated Individuals: Findings from USA, Canada, Sweden, and Italy

“…Societal freedoms capture concerns related to what will and will not be allowed based on vaccination status including freedom of movement, freedom of vaccine choice, and freedom of speech related to the vaccine itself. Though some of these specific survey items have been identified in the literature from a single country [ 13 , 14 , 15 , 31 , 32 , 33 , 34 ] this is the first analysis to identify that these concerns were common in multiple countries at the same time. This demonstrates that concerns are not limited to one country, but rather spread across borders.…”

“…The Vaccine effects factor may reflect exposure to misinformation narratives—including issues related to vaccine contents, fertility, impact on DNA, etc. that emerged related to the vaccine [ 14 , 15 , 18 , 37 ]. The consistency in relationship between this factor and hesitancy, suggests that these themes were circulating across all four countries, and implies that these narratives may have been the ones to focus on globally in the fight against misinformation.…”

“…Early identification of narratives of concern- such as those related to the development and effect of the vaccine could be a particular focus area for collaborative efforts. Additionally, all of the three themes we identified as having an effect on vaccine hesitancy in May 2020, are still prevalent online in more recent analyses of online and offline narratives [ 13 , 14 , 49 ]. Given that vaccine hesitancy is still an issue in many countries rolling out booster shots, the relationships identified here, and the relative importance of each of these factors in each country, can be helpful in the development of communication efforts on the narratives that seem to have the greatest effect in that country.…”

“…In Italy, Moscardino et al found that concerns about the vaccine’s efficacy contributed to vaccine hesitancy among young adults [ 13 ]. Studies from both Canada and Sweden have documented concerns regarding vaccine side effects, particularly allergic reactions, as well as about the country of origin of the vaccine [ 14 , 15 , 16 ]. Further, literature from all four countries demonstrates greater rates of vaccine hesitancy among those who have children than those who do not.…”

Increased Online Aggression During COVID-19 Lockdowns: Two-Stage Study of Deep Text Mining and Difference-in-Differences Analysis

“…General sentiment analysis has been performed to examine people's emotions under lockdown [16,17]. Some are related to specific topics, such as vaccination [18][19][20], while others are related to specific regions or countries [21]. However, most studies did not analyze the relationship between lockdown and emotions to the best of our knowledge.…”