JMIR Publications

ABSTRACT

Background:

Social media enables the rapid consumption of news related to COVID-19, and serves as a platform for discussions. Its richness in text-based data in the form of posts and comments allows researchers to identify popular topics and assess public sentiment. Yet, the vast majority of this type of work is done on the platform or country level, and does not account for local culture and policies.

Objective:

The aim of this study is to use location-based subreddits on Reddit to study city-level variations in sentiments towards vaccine-related topics.

Methods:

Comments made on posts providing regular updates on COVID-19 statistics in the Vancouver, Toronto, and Calgary subreddits (r/vancouver, r/toronto, r/calgary) between July 13th, 2020 and June 14th, 2021 were extracted (N = 49,291, 20,764, and 21,277, respectively). Latent Dirichlet allocation was used to identify frequently discussed topics. Sentiment (joy, sadness, fear, and anger) scores were assigned to comments using random forest regression.

Results:

Beginning by focusing on the Vancouver subreddit, the number of comments made on each post positively correlated with the number of new cases (P < 0.001). From the comments, thirteen topics were identified. Two were related to vaccines, one regarding vaccine uptake and the other about vaccine supply. The levels of discussion for both topics were linked to the total number of vaccinations given (Granger test for causality: P < 0.001). Comments pertaining to either topic displayed higher scores for joy compared to comments about other topics (P < 0.001). Calgary and Toronto also discussed vaccine uptake. Sentiment scores for this topic differed across the three cities (P < 0.001).

Conclusions:

Overall, our work demonstrates that comments from Reddit can be used to better understand concerns and sentiments surrounding the pandemic at the local level, which enables more targeted and publicly-acceptable policies.