Which vaccine is administered through the intranasal route?

The influenza (live) vaccine is administered through the intranasal route, making it distinct from the other options listed. This vaccine delivers live attenuated virus through the nasal passages, providing a convenient and non-invasive means of vaccination. Intranasal administration is particularly beneficial, as it stimulates both systemic and mucosal immunity, which is vital for respiratory viruses like influenza.

In contrast, the rotavirus vaccine is typically administered orally, the varicella virus vaccine is given via subcutaneous injection, and the human papillomavirus vaccine is administered intramuscularly. Each of these vaccines targets different viruses and utilizes varying routes of administration based on efficacy, safety, and the nature of the immune response required. The uniqueness of the intranasal route in the context of the influenza vaccine makes it the correct answer in this case.