Which key question is important to ask a patient before administering IIV?

The most important question to ask a patient before administering the inactivated influenza vaccine (IIV) is whether the patient is currently sick. This question is crucial because it helps assess the patient's overall health status at the time of vaccination. If the patient is experiencing moderate to severe illness, potentially with fever or other significant symptoms, it may be advisable to defer vaccination until they have recovered. This precaution aims to ensure that the immune response to the vaccine is optimal and that the patient does not experience additional strain or complications from vaccination while unwell.

While the other options include important aspects to consider, they do not address the patient's immediate health status as directly as asking if they are sick today. Knowing whether the patient is currently unwell helps clinicians make informed decisions about the appropriateness and timing of vaccination.