Vaccinations work best when everyone in a population gets them because of a phenomenon known as herd immunity. When a large percentage of a population is vaccinated against a disease, it becomes much harder for the disease to spread, as there are fewer susceptible individuals for it to infect. This means that even people who are not able to receive the vaccine (such as those with weakened immune systems) are protected because the disease is less likely to be circulating in the community. Additionally, when the chance of transmission is reduced, the probability of potential mutations decreases, as the virus has fewer opportunities to evolve and adapt. Therefore, the more people that get vaccinated, the stronger the herd immunity, and the better the protection for everyone in the population.
