Yes! Immunizations are thoroughly studied before they are licensed for public use. Vaccines, before they are approved in the United States go through a rigorous process to assess their safety. The link the the brochure below describes the entire process, and also the continued evaluation of vaccines. Clinical trials are conducted to evaluate the safety and effectiveness of any single or combination vaccine before it can be brought to the market. Once a vaccine is introduced, there is a strong system in place to continuously monitor its safety. Vaccine safety is a shared responsibility among the federal government, state and local health departments, other partners and the public. To help meet this shared responsibility, government agencies and their partners have established several coordinated systems to monitor the safety of vaccines after they have been licensed for public use. These systems, such as the Vaccine Adverse Event Reporting System (VAERS), are used together to help scientists continuously monitor issues.