Safety and efficacy of vaccines.

For the past two centuries, vaccines have provided a safe and effective means of preventing a number of infectious diseases. Although the safety of some vaccines has been questioned in recent years, the currently available vaccines are more than a millionfold safer than the diseases they are designed to prevent. Vaccines, however, should always be used in conjunction with other public health interventions. One important intervention is education because the general public can be led to believe that vaccines are unsafe and not needed by misinformation readily available electronically and in print. Not only are some vaccines available via injection but other vaccines are also given orally or intranasally. New vaccines are being studied for topical and intravaginal use. In addition, new systems are being developed for more efficient production of vaccines, especially for influenza. Vaccines are currently available for only a limited number of viral and bacterial diseases. In the future, it is anticipated that safe and effective vaccines will be developed against a number of other viral and bacterial infections as well as fungal and protozoan diseases.