The COVID-19 vaccine will help protect people against COVID-19. Both adults and children can have some side effects after the vaccine, which are normal signs that their bodies are creating protection. These side effects may affect your ability to do daily activities, but they should go away in a few days. Some people have no side effects, and allergic reactions are rare. It is highly unlikely that after receiving any vaccine, including the COVID-19 vaccine, there will be serious side effects that will cause a long-term health problem. Vaccination monitoring has historically shown that side effects generally occur within six weeks of vaccine administration. For this reason, the United States Food and Drug Administration (FDA) collected data from all licensed COVID-19 vaccines for a minimum of two months (eight weeks) after the last dose. The CDC continues to monitor the safety of COVID-19 vaccines even as they are being used.