Which statement describes the influenza vaccine used annually?

• A. Live attenuated
• B. Inactivated
• C. Toxoid
• D. Recombinant

Answer: (B)

The vaccine used every year for influenza is an inactivated vaccine. An inactivated vaccine contains killed virus, so it cannot replicate or cause influenza, but it still prompts the immune system to produce antibodies against the circulating strains chosen for the season. This makes it safe for a broad population and suitable for routine annual use, typically delivered by injection. Live attenuated vaccines, which are given as a nasal spray, use a weakened form of the virus and have more restrictions on who can receive them, so they aren’t the standard option for everyone. Toxoid vaccines target bacterial toxins, not viruses like influenza, and recombinant vaccines are another platform that can be used in some seasons, but the classic annual description is that the influenza vaccine is inactivated.