The Attenuated Oral Poliovirus Vaccine (OVP) is No Longer Administered

Question

The attenuated oral poliovirus vaccine (OVP) is no longer administered in the U.S.A. because it
A) is very toxic.
B) does not provide good immunity.
C) can revert to wild-type virulence.
D) can be spread to contacts.
E) can be spread to contacts and can revert to wild-type virulence.

Accepted Answer

The attenuated oral poliovirus vaccine (OPV) can indeed revert to a more virulent form and be spread to contacts, which is why it is no longer administered in the U.S. This reversion to a more virulent form can potentially cause vaccine-derived poliovirus infections in non-immunized individuals.