Which of the following is NOT a purpose of genetic sequencing of poliovirus isolates in surveillance?

• A. Identify serotype, determine relatedness to Sabin vaccine strains, detect vaccine-derived strains, and trace transmission chains.
• B. Predict the exact day of symptom onset in a patient.
• C. Determine the color of the virus in culture.
• D. Monitor vaccine storage temperatures.

Answer: (B)

Genetic sequencing of poliovirus isolates is used to map the virus at a molecular level so public health teams can track its origin and spread. It helps identify which serotype is involved, see how closely an isolate matches Sabin vaccine strains, detect vaccine-derived polioviruses, and trace transmission chains across communities or regions. This molecular information supports outbreak identification, understanding transmission networks, and monitoring viral evolution over time.

Predicting the exact day of symptom onset in a patient isn’t something sequencing can do. The onset day depends on factors like the incubation period, exposure timing, and individual host responses—data that aren’t determined by the virus’s genome sequence. Sequencing won’t tell you the color of the virus in culture or monitor vaccine storage temperatures, which are separate lab and operational measurements.