Lecture 21: COVID 19

Question 1

What is the pattern of inflammation for covid?

Answer 1

Pattern of inflammation in interstitium and alveoli

Question 2

What are the potential treatments for covid?

Answer 2

Target the immune system:

- Dexamethasone and tociluzimab (monoclonal AB)

Question 3

How does sars-cov2 bind to resp. epithelium?

Answer 3

Spike protein binds to ACE2 in the human nasopharynx

Question 4

What happens following the virus binding to ACE 2 receptor?

Answer 4

• Protein invaginated
• Viral RNA inserted into genome
• Replicase replicates RNA (but has a high mutation rate), virus made and released

Question 5

What are the outcomes of SARS-Cov 2 infection of the resp. epithelium?

Answer 5

• No symptoms
• Mild disease (majority)
  
  • Coryza/anosmia
  • Cough and sore throat
  • Dyspnoea, fatigue, reduced exercise tolerance
• Severe disease
  
  • Severe pneumonia
  • Sepsis
  • Multi-organ failure

Question 6

How do the inflammatory markers reflect the different responses to covid?

Answer 6

Mild covid has:

• Macrophages and dendritic cell recruitment
• Cytotoxic T cells

Transition from mild to severe covid (Damage associated molecular patterns (DAMP) and pathogen associated molecular patterns PAMP i.e bind TLR)

Severe covid
- Cytokine storm!!
= Organ failure (hyperinflammatory phase)

Question 7

What are the risk factors for covid?

Answer 7

Age
Male
Higher BMI
Smoking
Hypertension
Diabetes
CV disease
Chronic lung disease

Question 8

Why do a small amount of children develop severe covid?

Answer 8

1. Lack of risk factors
2. Less impact of pollution/smoking
3. Different upper resp. tract flora
4. Robust innate immune response with immature adaptive immune response
5. Different ACE2 expression
6. Protection from childhood vaccines (MMR)
7. Less travel, less exposure

Question 9

Why do new variants sweep through populations?

Answer 9

B/c recombination or mutation = selection pressure of genetic DRIFT