Adverse effect of vaccines and biological substances, subs

This code describes a patient experiencing an undesirable or harmful reaction to a vaccine or other biological substance, such as antitoxins or immune globulins, during a follow-up visit for the adverse effect. It indicates that the initial adverse event has already occurred, and the patient is now being seen for ongoing management, monitoring, or resolution of the reaction.

Use this code when a patient presents for a subsequent visit related to an adverse effect from a vaccine (e.g., flu shot, tetanus shot) or other biological substance (e.g., antivenom, interferon). This applies to scenarios such as follow-up for persistent rash, prolonged fever, or other complications that developed after the initial administration of the biological agent.

• Always sequence this code after the code(s) identifying the specific manifestation of the adverse effect.
• Ensure documentation clearly states the adverse effect is from a vaccine or biological substance and that it's a subsequent encounter.
• Do not use for adverse effects of drugs or medications; refer to the T36-T50 categories for those.