Obviously, the best way to prevent is to get vaccinated. The probability of not contracting the disease increases when more vaccines are given in the community. Its called "Herd Immunity". Herd immunity is a form of immunity that occurs when the vaccination of a significant portion of a population provides a measure of protection for individuals who have not developed immunity. It arises when a high percentage of the population is protected through vaccination against a virus or bacteria, making it difficult for a disease to spread because there are so few susceptible people left to infect.
This can effectively stop the spread of disease in the community. It is particularly crucial for protecting people who cannot be vaccinated. These include children who are too young to be vaccinated, people with immune system problems, and those who are too ill to receive vaccines (such as some cancer patients). The principle of community immunity applies to control of a variety of contagious diseases, including influenza, measles, mumps, rotavirus, and pneumococcal disease.
The proportion of the population which must be immunised in order to achieve herd immunity varies for each disease but the underlying idea is simple: once enough people are protected, they help to protect vulnerable members of their communities by reducing the spread of the disease.
However, when immunisation rates fall, herd immunity can break down leading to an increase in the number of new cases. For example, measles outbreaks in the UK and pertussis outbreaks in the US have been attributed to declining herd immunity. The principle of community immunity applies to control of a variety of contagious diseases, including influenza, measles, mumps, rotavirus, and pneumococcal disease. So next time your doctor recommends vaccination, you remember that it not only prevents disease to you but to your loved ones and the ones who cannot get vaccines and to strengthen the herd immunity.