  The outbreak of the novel Coronavirus Disease 2019 (COVID-19) has lasted for
nearly two years and caused unprecedented impacts on people's daily life around
the world. Even worse, the emergence of the COVID-19 Delta variant once again
puts the world in danger. Fortunately, many countries and companies have
started to develop coronavirus vaccines since the beginning of this disaster.
Till now, more than 20 vaccines have been approved by the World Health
Organization (WHO), bringing light to people besieged by the pandemic. The
promotion of COVID-19 vaccination around the world also brings a lot of
discussions on social media about different aspects of vaccines, such as
efficacy and security. However, there does not exist much research work to
systematically analyze public opinion towards COVID-19 vaccines. In this study,
we conduct an in-depth analysis of tweets related to the coronavirus vaccine on
Twitter to understand the trending topics and their corresponding sentimental
polarities regarding the country and vaccine levels. The results show that a
majority of people are confident in the effectiveness of vaccines and are
willing to get vaccinated. In contrast, the negative tweets are often
associated with the complaints of vaccine shortages, side effects after
injections and possible death after being vaccinated. Overall, this study
exploits popular NLP and topic modeling methods to mine people's opinions on
the COVID-19 vaccines on social media and to analyse and visualise them
objectively. Our findings can improve the readability of the noisy information
on social media and provide effective data support for the government and
policy makers.
