In December 2019, China identified a new coronavirus causing respiratory infections that can quickly turn into pneumonia. There are currently several vaccines available that protect against this infection and significantly reduce the chance of getting sick and especially reduce the risk of severe illness. The collection of microorganisms in our bodies (microbiome) has been linked to vaccine responses, suggesting potential ways in which it might affect how well the vaccines work. Several factors, including our body characteristics, what we eat, how we were born, our behaviors, and the environment around us, can also influence how our bodies respond to vaccines. These factors also affect our general immunity and the microorganisms in our bodies. Moreover, vaccine factors have also an influence on the ability of a vaccine to provoke an immune response in our body. Additionally, the characteristics of the vaccine also play a role in how effective the vaccine is in generating an immune response. Articles were collected from three medical databases. Results showed that changes occur in the diversity and types of microorganisms in our bodies after getting vaccinated. Other studies even looked at how antibiotics might affect vaccination, and they found a slight decrease in response to vaccination, but no major differences in side effects after vaccination. Other studies showed that certain types of microorganisms are linked to how people respond to vaccination. For example, people with certain chronic health conditions, like HIV or inflammatory bowel disease, might not respond as well to the vaccines as healthy people. Researchers also studied how our weight might play a role in how well we respond to vaccines. They found that people with different body mass indexes (BMI) had different responses, and the types of microorganisms in their bodies were linked to how well the vaccines worked. Another interesting finding was about what we eat. People with different levels of fiber in their diets had differences in the types of microorganisms in their guts, and this could affect how well they respond to vaccines. Lastly, some researchers looked at what happens when they simulate the digestion of breast milk samples in a way similar to how it happens in infants. They found that certain antibodies decreased after digestion, but this didn't seem to change the microorganisms in the large intestine. This suggests that interventions focusing on the microbiota or its metabolites have the potential to significantly improve the body's response to vaccines. Additionally, these interventions may contribute to reinforcing the long-lasting effectiveness of the protection provided by the vaccines. The included studies help us understand more about how our bodies and the microorganisms inside us respond to vaccines. This knowledge can help us improve the way we protect ourselves from diseases, especially COVID-19. Understanding the link between the microbiome and vaccine responses opens up opportunities for personalised vaccination approaches. By considering factors such as our body characteristics, what we eat, how we were born, our behaviors, and the environment around us, healthcare providers could tailor vaccination plans to improve vaccine effectiveness, i.e. the extent to which a vaccine protects against a specific disease or infection under real-world conditions. Moreover, research on the influence of antibiotics, chronic diseases and body weight on vaccine responses highlights the need for targeted interventions for specific population groups. This knowledge contributes to the development of more inclusive vaccination strategies to ensure that different population groups receive adequate protection.