Impact of Public Health Event on COVID-19 Vaccine Hesitancy on Social Media: National Infoveillance Study.

BACKGROUND The ongoing Coronavirus 2019 (COVID-19) pandemic has brought unprecedented challenges to every country in the world. A call for global vaccination of COVID-19 plays a pivotal role in the fight against this virus. With the development of COVID-19 vaccines, public willingness to accept a vaccination has become an important concern of public health given the vaccine hesitancy observed in the world. Social media is powerful in monitoring public attitudes and assess the dissemination, which would provide valuable information for policy makers. OBJECTIVE This study aimed to investigate the responses of vaccine positivity on social media when major public events (major outbreaks) or major adverse event of vaccination (COVID-19 or other similar vaccines) were reported. METHODS A total of 340,783 vaccine-related posts was captured with the poster's information on Weibo, the biggest social platform in China. After data cleaning, 156,223 posts were included in the subsequent analysis. By using pandas and SnowNLP Python libraries, posts were classified into 2 categories, positive and negative. After model training and sentiment analysis, the proportion of positive posts was computed to measure the public positivity toward the COVID-19 vaccine. RESULTS The positivity of COVID-19 vaccine in China tends to fluctuate over time in the range of 45.7% to 77.0% and is intuitively correlated with public health events. In terms of gender, males were more positive (70.0% of the time) than females. In terms of region, when regional epidemics arose, not only the region with the epidemic and surrounding regions but even the whole country showed more positive attitudes to varying degrees. When the epidemic subsided temporarily, positivity decreased with varying degrees in each region. CONCLUSIONS In China, public positivity of COVID-19 vaccines fluctuates over time and a regional epidemic or news on social media may cause significant variations in willingness to accept a vaccination. Furthermore, public attitudes of COVID-19 vaccination vary from gender and region. It is crucial for policy makers to adjust their policies through the use of positive incentives with prompt responses to pandemic-related news to promote vaccination acceptance. CLINICALTRIAL