Question

The influenza vaccine is administered each year because
A.mutations in the viral hemagglutinin may allow the virus to evade the immune response elicited by previous vaccines
B. it is a polysaccharide vaccine that does not confer long-term protection
C. the vaccine is sufficiently toxic to make it necessary to administer only a small amount at any one time
D. none of the above

Answer 1

Answer:

c. the vaccine is sufficiently toxic to make it necessary............