During a visit to a hospital, a child receives the oral polio vaccine. He then returns to his distant village. Sometime later a polio outbreak occurs in the village, but the child and his siblings, who had not had the vaccine, are spared. What is the explanation for this event?

Question

Quizplus · Accepted Answer

Contact immunity occurs when a vaccinated individual, especially with live attenuated vaccines like the oral polio vaccine, can spread the vaccine virus to others, indirectly immunizing them. This can protect unvaccinated individuals in close contact with the vaccinated person.

During a Visit to a Hospital, a Child Receives the Oral