covid 19

Question 1

Coronaviruses and thier name

Answer 1

are a large family of enveloped, single-stranded, RNA viruses that circulate among animals including camels, cats, and bats.
Coronaviruses derive their name from their electron microscopic image, which resembles a crown – or corona

Question 2

cronavirus progration

Answer 2

2003: sars in chine
2012: mers in ksa
2019: unknown etiology pnemonia in wuhan china
2020: full genome of new corona virus (SARS-CoV-2) had been sequenced

Question 3

Covid-19 Virus name

Answer 3

The virus was initially referred to as “novel coronavirus 2019” (2019-nCoV) by the WHO
On February 11, 2020, was given the official name SARS-CoV-2 by the International Committee on Taxonomy of Viruses

Question 4

Covid-19 Virus spike protiens and subunits

Answer 4

SARS-CoV-2 has a SPIKE PROTEIN that is composed of two subunits, S1 and S2
The S1 subunit contains a receptor-binding domain that recognizes and binds to the host ACE2 receptors
The S2 subunit mediates virus entry into the cell and plays a role in the increased viral infectivity

Question 5

the pathological reason for covid-19 deaths is

Answer 5

“cytokine storm” which is also called “cytokine storm syndrome”
Cytokine storm is described as “a systemic inflammatory response to infections and drugs and leads to excessive activation of immune cells and the generation of pro-inflammatory cytokines”

IL-6, IL-1β & TNF-α compared to those who are moderately ill

Question 6

Postmortem examinations of covid 19 patienrs

Answer 6

Excessive infiltration of pro-inflammatory cells, mainly involving macrophages and T-helper 17 cells, has been found in lung tissues of patients with COVID-19 by postmortem examination.

Question 7

Pathological Consequences of cytokine syndrome

Answer 7

The cytokine storm can lead to
* apoptosis of epithelial cells and endothelial cells
* vascular leakage
* ARDS, other severe syndromes, and death

Question 8

clinical presentation and incubation period

Answer 8

The disease caused by the SARS-CoV-2 virus is known as coronavirus disease -2019 or COVID-19.
The majority of patients will be asymptomatic
The incubation period for COVID-19 extend to 14 days, with a median time of 4-5 days from exposure to symptoms onset. This varies according to strains.

Question 9

S & S of covid 19

Answer 9

Fever or chills
Shortness of breath or difficulty breathing (more common in severe disease)
Fatigue & body aches
Headache
New loss of taste or smell
GI symptoms e.g. Nausea or vomiting, Diarrhea
Congestion or runny nose
Sore throat

Question 10

COVID-19 Testing Methods

Answer 10

1. Antigen Testing
2. RT-PCR (Gold standard)
3. Serologic (Antibody) testing

Question 11

1. Antigen Testing

Answer 11

Antigen tests are **immunoassays **designed to detect specific viral antigens, such as COVID-19 proteins. These tests are typically performed using nasopharyngeal or nasal swab specimens, which are placed directly into the assay’s extraction buffer or reagent. Key characteristics of antigen testing include:
* given result in 15 mins
* inexpensive
* less sensitive

Question 12

RT-PCR

Answer 12

Specimen Collection: Nasopharyngeal swabs are preferred. Proper swab insertion is critical to avoid false negative results.
Transport and Storage: Swabs should be transported to the lab in universal transport media or saline and stored at 2–8°C. They should not be sent via pneumatic tubes.
Sensitivity: RT-PCR is highly sensitive and can detect the virus even in asymptomatic patients.

Viral Load: Viral loads are higher in severe disease compared to mild cases. Most patients with mild disease test negative by 10 days post-symptom onset, while those with severe disease may test positive for up to 20 days. The virus may be detectable until death in some non-survivors.

Question 13

Serologic (Antibody) testing

Answer 13

Serologic tests detect antibodies (IgG and/or IgM) that form in response to SARS-CoV-2 infection. Techniques used include ELISA and chemiluminescent
Antibodies may take up to 14 days to form, making these tests unsuitable for early diagnosis.
While not ideal for diagnosing active infections, antibody tests are useful for detecting past infection and assessing potential immunity.

Question 14

Treatments for COVID-19

Answer 14

1. Antimalarials
2. Antiviral Therapy
3. Dexamethasone
4. Biologics
5. Convalescent Plasma

Question 15

1. Antimalarials

Answer 15

Hydroxychloroquine: Initially showed promise as it interfered with SARS-CoV entry into cells (2002 study).
Early reports from China and France suggested that patients with severe symptoms of COVID-19 improved more quickly when given antimalarials.
The antimalarials appear to work through 2 mechanisms:
* they inhibit fusion of the virus to the cell
* if the virus enters the cell, the drugs kills it before it can replicate.
Azithromycin: An antibiotic with anti-inflammatory properties.
However, with Covid-19, human studies suggest no benefit and possibly a higher risk of death due to fatal cardiac arrhythmias caused by D/D interaction.

Question 16

2. Antiviral Therapy

Answer 16

Most effective early in the disease when viral replication is high.
Remdesivir: Inhibits RNA virus transcription, shortens recovery time by about three days in hospitalized patients requiring supplemental oxygen. Not recommended for those on mechanical ventilation due to insufficient data on its efficacy in advanced stages.
Other Antivirals: Ritonavir and Nirmatrelvir (Paxlovid) are also used in treatment.

Question 17

3. Dexamethasone

Answer 17

Corticosteroid Use: Historically used in SARS and MERS; however, previous meta-analyses indicated increased mortality and delayed viral clearance.
COVID-19 Application: Administered to ICU patients to suppress the cytokine storm by inhibiting gene transcription and action of cytokines.
Dexamethasone benefit is more in hospitalized patients who require supplemental oxygen, with the greatest effect observed in patients who require mechanical ventilation.

Question 18

4. Biologics

Answer 18

Tocilizumab: recombinant monoclonal antibody that targets the interleukin-6 (IL-6) receptor. By binding to the IL-6 receptor, tocilizumab prevents IL-6 from exerting its effects

Bamlanivimab + etesivimab, casirivimab + imdevimab have been approved to treat non-hospitalized adults and children over age 12 with mild to moderate symptoms who have recently tested positive for Covid-19, and who are at risk for developing severe Covid-19 or being hospitalized for it.

Question 19

5. Convalescent plasma

Answer 19

has been used for more than 100 years to treat a variety of illnesses such as measles, polio, chickenpox, and SARS and widely believed to be safe.
In covid-19, antibody-containing plasma from a recovered patient is given by transfusion to patients suffering from the disease.
The use of convalescent plasma in covid-19 is based on its content of antibodies against SARS-CoV-2 that may help the recipient patient fight the illness, possibly shortening the length or reducing the severity of the disease.

Question 20

Genetic (DNA and RNA) Vaccine:

Answer 20

. mRNA technology has shown that when synthetic mRNA is injected into animal, the cells can produce the desired protein
The mRNA COVID-19 vaccines are the 1st using this technique.
mRNA vaccines are lipid nanoparticle–encapsulated, nucleoside-modified mRNA based vaccine that encodes the SARS-CoV-2 spike glycoprotein (mediates host cell attachment and is required for viral entry)

Question 21

advantages of Genetic (DNA and RNA) Vaccine:

Answer 21

1. mRNA Vaccines can be developed faster
2. mRNA molecules are far simpler than proteins
3. mRNA production avoids the common risks associated with other vaccine
4. mRNA vaccines are more effective because of better immunological advantage
5. Less cost in production

Question 22

Safety Covid-19 vaccines:

Answer 22

• Remember that no vaccine (actually, nothing in medicine) is 100% safe.
• mRNA vaccines can’t cause an infection, because its free from live or attenuated virus
• mRNA doesn’t enter the cell’s nucleus, so the chance of its integration into human DNA is believed to be very low.

Question 23

How Long Do Antibodies Against COVID-19 Last?

Answer 23

Infection with this coronavirus does not generate lifetime immunity
* Covid-19 vaccines may provide protection for months or years, but not the whole life.
* Antibodies are not the whole story here. The immune system does remember how to make new antibodies when needed and other parts of the immune system play a role in this.