If a vaccine is DIVA compatible, what does that mean?

• A. DIVA allows serology to differentiate infected from vaccinated animals.
• B. DIVA implies vaccines provide sterilizing immunity.
• C. DIVA eliminates the need for surveillance.
• D. DIVA relies solely on clinical signs.

Answer: (A)

DIVA compatibility means you can tell apart antibodies generated from vaccination versus those generated by natural infection. In practice, a DIVA-compatible vaccine is designed with a marker or a missing/altered antigen, and a companion serologic test detects antibodies that indicate infection rather than vaccination. This lets surveillance identify infected animals even in vaccinated populations, which is crucial for disease control and trade decisions. The other ideas aren’t what DIVA describes: sterilizing immunity is about preventing any infection, not about distinguishing infection status; vaccination doesn’t remove the need for surveillance; and relying only on clinical signs isn’t reliable for differentiating vaccinated from infected animals.