Adverse Reactions

to Vaccines Adverse reactions to vaccines are undesirable reactions that occur after a person is immunized with a vaccine. These reactions can be mild or severe. Common examples of mild reactions include redness, itching, and swelling at the injection site, fever, and aches. Severe reactions may include anaphylaxis, a life-threatening allergic reaction. It is important to monitor for adverse reactions to vaccines, as they can help identify any safety issues with a particular vaccine. The effectiveness of a vaccine in preventing the target disease is important, but safety is the most important factor when it comes to public health. Vaccines have been largely responsible for the global decrease in infectious disease rates since the mid-20th century, and monitoring for adverse reactions is essential for maintaining the safety of these life-saving vaccines.