Viral pandemics Influenza and Coronaviruses Flashcards

1
Q

What are three requirements for a virus to become a pandemic?

A

A pandemic virus will have novel antigenicity.

A pandemic virus will replicate efficiently in human cells.

A pandemic virus will transmit efficiently between people.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the natural reservoir of influenza A viruses?

A. Pigs

B. Chickens

C. Ducks

D. Tigers

A

C. Ducks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which protein in human cells can support influenza replication?

A

ANP32 proteins are essential host cofactors that support influenza polymerase activity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can influenza polymerase utilise shorter mammalian ANP32?

A

Influenza polymerase can adapt to utilize shorter mammalian ANP32 homologues by mutation in PB2 subunit.

Polymerase adaptation to mammals can be achieved by a single amino acid change in PB2 E627K.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What needs to change in order for virus to successfully infiltrate humans?

A

Incoming virus needs to penetrate mucus and infect epithelial cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What contributes to incompatibility of avian-origin influenza virus with human respiratory tract?

A

Low acidic pH of URT followed by neutral pH of LRT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why is influenza A currently incompatible with human-human transmission?

A

Avian influenza HA must adapt for transmission in humans by acquiring affinity for human receptors.

Influenza entry is pH dependent and HA protein is pH sensitive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Are antiviral medications for influenza used together or separately?

A

Antiviral medications for influenza are NOT licensed to be used together (like HAART).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are examples of neuraminidase inhibitors?

A

Oseltamivir

Zanamivir

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do new influenza antivirals target?

A

Polymerase acidic protein endonucleases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is an example of a polymerase acidic protein endonuclease inhibitor?

A

Baloxavir

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The influenza vaccine given to those at greater risk of complications from flu in the UK is:

A. A live attenuated virus.

B. A purified fraction containing HA and NA of an inactivated virus.

C. A purified HA protein expressed in insect cells.

D. An immunoglobulin fraction from sera of immune patients.

A

B. A purified fraction containing HA and NA of an inactivated virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the two types of influenza vaccine given in the UK?

A

Inactivated vaccine

Live attenuated vaccine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are features of the inactivated influenza vaccine?

A

Split or subunit- HA rich

Given to those at risk

Short term strain specific immunity mediated by antibody to HA head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are features of the live attenuated influenza vaccine?

A

Cold adapted virus limited to URT

Given to children

Broader more cross reactive immunity including cellular response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the major influenza viral antigen?

A

Haemagglutinin

17
Q

What is the structure of a influenza spike protein (HA)?

A
18
Q

Where do most broadly neutralising Abs (bnAb) target?

A

HA stalk/stem

19
Q

To which parts of HA do current influenza vaccines generate a response?

A

Current vaccines generate specific Ab responses raised against immunodominant HA1 epitopes at five antigenic sites (Sa, Sb, Ca1, Ca2, Cb).

20
Q

What are coronaviruses?

A

RNA genomes, single stranded positive sense RNA, very large genomes.

Enveloped virions. 100nm

Nidovirales - A nested set of mRNAs from one large genome

21
Q

Which coronaviruses have caused disease in humans?

A

OC43, 229E, NL-63 and HKU-1 cause 20-30% common colds

SARS and MERS are zoonotic

22
Q

What do SARS and SARS-CoV2 bind to?

A

Angiotensin Converting Enzyme 2

23
Q

What causes the severe effects of coronavirus?

A

Virus dissemination

Immunopathology

24
Q

A COVID patient in ITU is most likely to benefit from:

A. Kaletra, a combination of lopinavir and ritonavir usually used to treat HIV.

B. Hydroxychloroquine, an antimalarial.

C. Remdesivir a nucleoside analogue.

D. Dexamethasone, a steroid.

A

D. Dexamethasone, a steroid.

25
Q

Why is dexamethasone used in COVID patients on ventilation?

A

Cheap and extensively used steroid.

RECOVERY trial found Dex was effective in those receiving oxygen or ventilated.

Reduced deaths in illest cohort by 1/3.

Now standard of care in UK.

26
Q

Which monoclonal antibodies have been trialed against COVID?

A

Regeneron

Sotrovimab

27
Q

Which small molecule antivirals have been trialed against COVID?

A

Molnupiravir: Targets polymerase, nucleoside analogue.

Paxlovid: Targets protease.

28
Q

Why is the COVID vaccine not effective against the Omicron variant?

A

Omicron has a large number of Spike mutations that affect antibody neutralization.