A nurse is reviewing the medical record for a child who is scheduled to receive a varicella immunization. Which of the following findings in the client's record should the nurse recognize as a contraindication?

The varicella vaccine is a live attenuated vaccine used to prevent varicella-zoster virus infection in children. Live vaccines stimulate an immune response using a weakened form of the virus and require a functioning immune system to be safe and effective. Immunocompromised clients are at increased risk for developing severe or disseminated infection from live vaccines. Therefore, identifying contraindications before administration is essential for patient safety. Rationale: A. Medications for a cardiac anomaly are not a contraindication to receiving the varicella vaccine. Many children with congenital heart conditions routinely receive immunizations unless specific immunosuppressive therapy is involved. The presence of a cardiac condition alone does not impair immune response to live vaccines. B. Two episodes of diarrhea in the last day are not a contraindication for vaccination. Mild acute illnesses, including gastrointestinal symptoms without systemic involvement, do not prevent vaccine administration. Vaccination may be delayed only in cases of moderate to severe illness with fever or significant clinical instability. C. Clear rhinorrhea is typically associated with a mild upper respiratory infection or allergies and does not contraindicate immunization. Minor illnesses without fever or systemic symptoms do not interfere with vaccine safety or efficacy. Therefore, vaccination can proceed as scheduled in such cases. D. Chemotherapy treatments are a contraindication to receiving the varicella vaccine because chemotherapy causes immunosuppression. A weakened immune system increases the risk of uncontrolled viral replication from a live attenuated vaccine. This can lead to severe or disseminated varicella infection, making vaccination unsafe during active treatment.