Rotavirus vaccine is classified as which type of vaccine?

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

Answer: (B)

How the immune system is exposed to the antigen determines vaccine type. The rotavirus vaccine uses a weakened form of the virus that can still replicate in the gut, so it stimulates a robust immune response, including mucosal immunity in the intestinal lining. This makes it a live attenuated vaccine. It's given orally to mimic natural infection at the site of rotavirus replication, which helps generate secretory IgA and lasting protection. Inactivated vaccines involve pathogens that are killed and cannot replicate, usually requiring boosters and yielding less mucosal immunity. Subunit vaccines use only specific viral proteins, not whole organisms, and Toxoid vaccines target inactivated toxins from bacteria; neither approach would rely on replicating a whole virus to confer protection.