Injection site nodules (ISNs) are a rare adverse event following immunisation (AEFI). Nodules can occur following the administration of an injected vaccine. They are most often asymptomatic, but may be intermittently tender, itchy, or show overlying skin changes. They generally resolve on their own without intervention.
We have recently updated our ISN reference page. The updated page includes information on ISN diagnosis, possible causes, and treatment, and recommendations for future vaccine doses.