Vaccination programs may help the world to reduce or eliminate Covid-19. Information about them may help countries to design theirs more effectively, with important benefits for public health. This article investigates whether it is possible to get insights into national vaccination programmes from a quick international comparison of public comments on Twitter. For this, word association thematic analysis (WATA) was applied to English-language vaccine-related tweets from eight countries gathered between 5 December 2020 and 21 March 2021. The method was able to quickly identify multiple international differences. Whilst some were irrelevant, potentially non-trivial differences include differing extents to which non-government scientific experts are important to national vaccination discussions. For example, Ireland seemed to be the only country in which university presidents were widely tweeted about in vaccine discussions. India's vaccine kindness term #VaccineMaitri was another interesting difference, highlighting the need for international sharing.