Question

A student received a flu shot in the fall. During the flu season, the student caught a cold. The most likely reason the vaccine he received did not prevent the cold was that:________.

a. his illness was not caused by a pathogen
b. he did not get the vaccine at the right time of year
c. his body produced antibiotics in response to the vaccine
d. the vaccine he received contained only flu virus antigens

Answer 1

D

Step-by-step explanation:

There are many different types of the flu and there are many different types of illnesses. Meaning that the vaccine could have only killed one strand of the flu or the student got a different type of sickness.

Answer 2

d. the vaccine he received contained only flu virus antigens

Step-by-step explanation:

Vaccine imparts immunity to the person by providing them the preformed antibodies or the weakened antigens. Flu shots carry the antigens of the flu virus (the influenza virus) and trigger the formation of memory cells against this virus. The presence of memory cells against the flue virus antigens makes the person immune to flu after vaccination.

However, cold is caused by a different virus (rhinovirus mainly) that have antigens distinct from that of the flu virus antigens. Therefore, a person vaccinated with flu shots would not have the memory cells or the preformed antibodies against the cold virus. This person can catch a cold when infected with the respective virus.