Question

According to the National Immunization Schedule, which types of poliovirus are contained in the Oral Polio Vaccine (OPV)?

• A. Type 1 only
• B. Type 1 and Type 2
• C. Type 1 and Type 3
• D. Type 1, Type 2, and Type 3

Hint:

Current OPV = \textbf{bOPV} (Type 1 + Type 3). Type 2 removed after eradication.

Answer 1

The Correct Option is C

Concept: Oral Polio Vaccine (OPV) is a live attenuated vaccine used to protect against poliomyelitis. Poliovirus has three serotypes: Type 1, Type 2, and Type 3. Historically, trivalent OPV (tOPV) contained all three types. However, after the global eradication of wild poliovirus Type 2, the vaccine was modified to bivalent OPV (bOPV), which contains only:

• Type 1 poliovirus
• Type 3 poliovirus

This change reduces the risk associated with vaccine-derived poliovirus Type 2.
Step 1: Understand the evolution of OPV.
Earlier vaccines included all three types, but current immunization schedules use bOPV.
Step 2: Identify the included types.
The present OPV contains Type 1 and Type 3 poliovirus strains.
Step 3: Eliminate incorrect options.
Options including Type 2 are outdated in the current schedule.
Step 4: Conclude the answer.
Thus, OPV contains Type 1 and Type 3 poliovirus.