The study looked at how the World Health Organization presented information about Covid-19 vaccines in posters for World Immunization Week 2021. They used a method called Systemic Functional Multimodal Discourse Analysis to analyze how the posters combined visuals and words to communicate with viewers. The results showed that when posters effectively combined visual and verbal elements, they were easier to understand and helped people grasp the message about vaccination. This means that by using a mix of pictures and words, the posters were able to effectively communicate the WHO's goals for the vaccination campaign.