Question

Question 25 1 pts A reason that we need to provide a new flu vaccine every year is: All other answers are correct O Spontaneous mutation of virus causing old vaccines to be ineffective Antigenic drift causing old vaccines to be ineffective Antigenic shift causing old vaccines to be ineffective Question 26 1 pts The apparent variety in symptoms and severity of COVID19 cases might be attributable to which factor? The virus targets a cell surface protein found in many cell types in humans The virus appears to be transmitted by the airborne route The virus uses 4 different structural proteins The virus is part of a family of viruses that have not been seen in humans before The virus mutates more rapidly once inside the human body

Answer 1

1. Antigenic drift causing old vaccines to be ineffective that's why we need to provide a flu vaccine every year. Antigenic drift is a gradual process of genetic change that leads to even more variety for each type of antigen.

2. The virus mutates more rapidly once inside the human body is an important factor due to which their are variety in symptoms and severity of COVID-19 cases.