Y59: Other and unspecified vaccines and biological substances

Y59.0: Viral vaccines

Viral vaccines are biological substances given to people to stimulate an immune response and provide immunity against specific viruses. These vaccines contain an agent that resembles disease-causing microorganisms and are often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins. When a person receives a viral vaccine, their immune system is primed to recognize and fight off the related virus if they are exposed to it in the future. Common side effects may include mild fever, aches, and redness or swelling at the injection site. Severe adverse reactions are rare but can include allergic reactions. Should such reactions occur after vaccination, they are regarded as medical conditions related to the administration of viral vaccines.