Based on current guidance, here are who typically should not receive a senior flu shot, or should proceed with caution, and why:

• People with a history of a serious allergic reaction to the influenza vaccine or any of its components. Anaphylaxis or other severe allergic reactions require consultation with a healthcare provider before vaccination. A prior severe vaccine reaction is a common reason to avoid or delay vaccination until evaluation. [sources summarized from public health guidance]
• Individuals with a fever or acute moderate-to-severe illness at the time of vaccination. It’s generally advised to postpone until you’re feeling better to ensure the best immune response and to avoid misattributing symptoms to the vaccine. [general vaccination practice]
• People who currently have a condition or are undergoing treatments that severely weaken the immune system, or those living with someone who is severely immunosuppressed (for example, a recent bone marrow transplant recipient). In such cases, a healthcare professional might recommend a different vaccination approach or timing. [specialist guidance]
• In some formulations, certain allergies (for example to eggs) or specific medical conditions may influence vaccine choice. If there are concerns about ingredients or immune status, a clinician may suggest an alternative vaccine type or postpone vaccination. [vaccine-specific considerations]

Important notes:

• The vast majority of adults 65 and older can receive the high-dose or adjuvanted flu vaccines, which are specifically recommended for older adults due to improved immune response. Exceptions are rare and typically involve the above allergy or immune-suppression concerns. A clinician can determine the most appropriate vaccine type and timing for individual cases. [age-focused vaccination guidance]

What to do next:

• If you or someone you’re helping has any of the conditions listed above, contact a healthcare provider or local public health clinic to review medical history, allergies, and current medications before scheduling the flu shot.
• If there’s uncertainty about symptoms, or if there’s a new or worsening illness, it’s prudent to postpone vaccination until cleared by a professional.

If you’d like, I can tailor this to a specific person’s medical history (for example, details about allergies, immune status, or current medications) and provide more precise guidance.