  Social media is an appropriate source for analyzing public attitudes towards
the COVID-19 vaccine and various brands. Nevertheless, there are few relevant
studies. In the research, we collected tweet posts by the UK and US residents
from the Twitter API during the pandemic and designed experiments to answer
three main questions concerning vaccination. To get the dominant sentiment of
the civics, we performed sentiment analysis by VADER and proposed a new method
that can count the individual's influence. This allows us to go a step further
in sentiment analysis and explain some of the fluctuations in the data
changing. The results indicated that celebrities could lead the opinion shift
on social media in vaccination progress. Moreover, at the peak, nearly 40\% of
the population in both countries have a negative attitude towards COVID-19
vaccines. Besides, we investigated how people's opinions toward different
vaccine brands are. We found that the Pfizer vaccine enjoys the most popular
among people. By applying the sentiment analysis tool, we discovered most
people hold positive views toward the COVID-19 vaccine manufactured by most
brands. In the end, we carried out topic modelling by using the LDA model. We
found residents in the two countries are willing to share their views and
feelings concerning the vaccine. Several death cases have occurred after
vaccination. Due to these negative events, US residents are more worried about
the side effects and safety of the vaccine.
