Herd immunity, also known as community immunity, is a concept where a large portion of a community becomes immune to a disease, making the spread of the disease unlikely. This is achieved through vaccinations, which help protect individuals from getting sick and also prevent the disease from spreading to others. By vaccinating a significant portion of the population, we can create a "herd" of immune individuals that acts as a barrier, protecting those who are unable to get vaccinated or have weakened immune systems. This not only helps protect individuals but also helps prevent outbreaks and ultimately saves lives.