VACCINES AND INFECTION

Question 1

Virus enters nasal cavity

Spike proteins

Bind to ACE2

To enter cells and replicate

Answer 1

VACCINATED

ABs designed specifically to attack the spike receptor domain in existence

They bind to the spike protein and inhibit the virus from entering the cells

Question 2

Viral load

Too high?

Not every virus will be ‘denied entry’ to the cells

Therefore, low-level infection will occur

Answer 2

EG 75% of virus particles are neutralised

Then 25% enter cells and replicate

And then go on to infect other cells

A great reduction on the initial load

Question 3

After ‘a few days’

ADAPTIVE immune system kicks in

B and T cells

Answer 3

B cells make ABs

Cytotoxic T cells seek and destroy infected cells

Question 4

Clinical burden

Answer 4

Symptom burden less

Symptom duration shorter

Faster clearance from the body

No progression to severe illness, hospitalization or death

Question 5

UNVACCINATED

And exposed

No ABs

Answer 5

No head start

No neutralizing capability

Body has to start from scratch

Worse symptoms

Longer duration

No memory B or T response

Question 6

TIMES 23 SEP

Prof Gilbert Oxford/AZ

Answer 6

She argued that the spike protein targeted by vaccines had only limited ability to mutate while still allowing the virus to get inside human cells. “If it changes its spike protein so much that it can’t interact with that receptor, then it’s not going to be able to get inside the cell. So there aren’t very many places for the virus to go to have something that will evade immunity but still be a really infectious virus,” she said.