The FDA and CDC monitor these reports weekly for routine safety purposes. Most vaccines are injected into the body, although a few can be swallowed by mouth. If injections are required, it is because stomach acid would prevent the vaccine from provoking a protective antibody response, or because not enough of the vaccine would get into the blood stream. Typically, vaccines administered by mouth correspond to a microbe that enters the body through the oral route. An influenza vaccine administered as a nasal mist showed promise in recent clinical studies.
Scientists routinely develop new vaccines or new recipes for existing vaccines.
As these improvements are found to be valuable, national policies change to reflect the current state of scientific knowledge. Everyone should have a personal record of vaccinations received during his or her lifetime. People should keep these records readily available and take them to health-care visits. Health-care providers keep records of vaccines they administer. State health departments are developing immunization registries to record this information centrally, a big help with a population as mobile as that of the United States.