Vaccination does carry some risk of complications. Getting the disease that you are being vaccinated against is not usually one of them. It is incredibly rare to contract a disease from its vaccine because the disease-causing agents have all been incapacitated. The oral polio vaccine (that is no longer recommend for use), did cause a few cases of polio in the past (a handful of people out of 2.5 million does administered), and there are a very small number of other cases in which a person has contracted a disease from its vaccine but the numbers are so small as to make the risk infinitesimally low. There is some risk of an injection site reaction, in which pain and redness can occur in the area where you got the shot. It is also possible to have a fever and feel a little ill a few hours after receiving a vaccination for certain diseases, but this usually goes away in a day or less.

Serious complications can also occur after a vaccination but they are also exceedingly rare. These serious health issues include severe allergic reactions that develop within a few minutes to a few hours of the shot, seizures, coma, and permanent brain damage. A serious nervous system disorder called Guillain-Barre Syndrome (GBS) may also be related to vaccination in rare cases but this link had not yet been well-established. The chances of serious complications are different depending on the vaccine but in most cases the risk is on the order of one in 100,000 to one in one million. This is akin to your risk of dying in an earthquake or a tornado. In most cases, the risk of serious complications or death from the disease you are being immunized against far outweighs any risks from the vaccine itself.

Some people feel like it is not important to be vaccinated against these diseases because many of them are now rare in the Western world (thanks to vaccinations). The problem with this point of view is that if people stop getting immunized, the entire population will be placed at greater risk of contracting these diseases that are now uncommon. The more people who are not vaccinated, the greater the likelihood of a resurgence of one or more of the diseases that are currently considered to be “under control.” Thus, it is important to be immunized not just to keep yourself healthy, but also to help maintain the immunity of the entire community.