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.

Question

Quizplus · 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.

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