Immunoprophylaxis

presentation
SDL

Roll no. 21-40

 Q1 What is immunoprophylaxis and its types?
Immunoprophylaxis** refers to the prevention of disease by inducing or enhancing immunity through the administration of immunological agents. It involves using vaccines or antibodies to protect individuals or populations from infectious diseases.

### **Types of Immunoprophylaxis**

There are two main types:

1. **Active Immunoprophylaxis**
- **Definition**: Involves stimulating the body's immune system to produce its own antibodies and memory cells.
- **Method**: Achieved by administering vaccines (live attenuated, inactivated, or subunit vaccines).
- **Examples**:
- Measles, Mumps, and Rubella (MMR) vaccine.
- Influenza vaccine.
- COVID-19 vaccines like mRNA-based vaccines (e.g., Pfizer-BioNTech, Moderna).
- **Duration**: Long-term or lifelong protection after a delay (time for immune response development).

2. **Passive Immunoprophylaxis**
- **Definition**: Involves administering pre-formed antibodies to provide immediate protection.
- **Method**: Antibodies can be derived from human or animal sources or produced synthetically (monoclonal antibodies).
- **Examples**:
- Hepatitis B immunoglobulin (HBIG) for post-exposure protection.
- Rabies immunoglobulin after potential exposure to the virus.
- Monoclonal antibodies for respiratory syncytial virus (RSV), such as Palivizumab.
- **Duration**: Short-term protection (antibodies degrade over time).

### **Key Differences Between Active and Passive Immunoprophylaxis**

| Feature | Active Immunoprophylaxis | Passive Immunoprophylaxis |
|-------------------------|-----------------------------|-----------------------------|
| **Immunity Source** | Self-generated (after stimulation). | Pre-formed antibodies. |
| **Onset of Protection** | Delayed (days to weeks). | Immediate. |
| **Duration of Effect** | Long-term. | Short-term. |
| **Memory Response** | Yes (memory cells formed). | No memory response. |

Immunoprophylaxis is a cornerstone of modern preventive medicine, helping to control and eradicate many infectious diseases.
Q2 What is a vaccine?
A vaccine is described as a biological preparation that provides active immunity to a specific infectious disease. The vaccine contains an agent that mimics a pathogen, typically in a
weakened or inactivated form, or as a fragment (such as a protein or toxin). By introducing this harmless version of the pathogen to the immune system, the vaccine prompts the body to
recognize the microorganism and produce a defense mechanism, usually in the form of antibodies, without causing the actual disease. This process enables the immune system to
"remember" the pathogen, allowing it to respond more effectively if it encounters the pathogen in the future.

vaccines can be classified into several types: live attenuated vaccines, which contain weakened forms of the virus or bacteria; inactivated vaccines, which contain killed pathogens; and
subunit vaccines, which include only specific components of the pathogen, such as proteins or antigens. The goal of vaccination is to build immunity in individuals, as well as in
populations, to prevent the spread of infectious diseases. Vaccines have been instrumental in reducing the global burden of diseases like polio, measles, and smallpox, contributing
significantly to public health improvements worldwide.
Q3 Discuss brief history of vaccines
1796- edward jenner, small pox
1872- louis pasteur, 1st lab produced vaccine, for fowl cholera in chicken
1885- louis pasteur successfully prevents rabies through post exposure vaccination
1894, Dr Anna Wessels Williams isolates a strain of the diphtheria bacteria that is crucial in the development of an antitoxin for the disease
1937-Max Theiler, Hugh Smith and Eugen Haagen develop the 17D vaccine against yellow fever.
By 1945, the first influenza vaccine is approved for military use, followed in 1946 by an approval for civilian use.
From 1952–1955, the first effective polio vaccine is developed by Jonas Salk and trials begin.
By 1960, a second type of polio vaccine, developed by Albert Sabin, is approved for use. Sabin’s vaccine was live-attenuated
In 1967, the World Health Organization announces the Intensified Smallpox Eradication Programme, which aims to eradicate smallpox in more than 30 countries through surveillance and vaccination.
In 1971 the measles vaccine (1963) is combined with recently developed vaccines against mumps (1967) and rubella (1969) into a single vaccination (MMR)
In 1974 the Expanded Programme on Immunization (EPI, now the Essential Programme on Immunization) is established by WHO to develop immunization programmes throughout the world. The first diseases
targeted by the EPI are diphtheria, measles, polio, tetanus, tuberculosis and whooping cough.
In 1980 the World Health Assembly, acting on recommendation from the WHO Global Commission for the Certification of Smallpox Eradication, declares smallpox eradicated
Q4 Describe newer vaccine approaches

• Newer vaccine approaches have shifted from traditional methods to more

innovative and targeted strategies. One of the key development is the use of
systems biology approaches, which involve a comprehensive understanding
of the complex interaction between host and pathogen

• This approaches utilizes high dimensional data acquisition techniques , such

as genomics , transcriptiomics , and proteomics , to characterise the immune
response to vaccines . By analysing this data , researchers can identify key
drivers of immunity and develop more e ective vaccines.
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Q5 Discuss characteristics of killed and live vaccines

Killed (Inactivated) Vaccines*

1. *Inactivated pathogens*: Killed vaccines contain inactivated or killed pathogens, such as bacteria or viruses, which cannot cause disease.
2. *No risk of infection*: Since the pathogens are inactivated, there is no risk of infection from the vaccine itself.
3. *Limited immune response*: Killed vaccines typically induce a limited immune response, which may not provide long-term immunity.
4. *Boosters required*: Killed vaccines often require booster shots to maintain immunity.
5. *Examples*: Influenza vaccine, Hepatitis A vaccine, and IPV (Inactivated Poliovirus Vaccine).

*Live (Attenuated) Vaccines*

1. *Weakened pathogens*: Live vaccines contain weakened or attenuated pathogens, which cause a mild or asymptomatic infection.
2. *Risk of infection*: Although rare, there is a small risk of infection from live vaccines, especially in immunocompromised individuals.
3. *Stronger immune response*: Live vaccines typically induce a stronger and more long-lasting immune response, often providing lifelong immunity.
4. *Fewer boosters required*: Live vaccines often require fewer booster shots, as the immune system remembers the infection and can respond quickly to future exposures.
5. *Examples*: MMR (Measles, Mumps, and Rubella) vaccine, Varicella (Chickenpox) vaccine, and OPV (Oral Poliovirus Vaccine).

*Key differences*

1. *Immune response*: Live vaccines induce a stronger and more long-lasting immune response, while killed vaccines induce a limited response.
2. *Risk of infection*: Live vaccines carry a small risk of infection, while killed vaccines do not.
3. *Booster requirements*: Live vaccines often require fewer booster shots, while killed vaccines may require more frequent boosters.
Q6 Discuss National Immunisation Schedule

• Provides free immunization to prevent diseases preventable by vaccines

• Target groups are children and pregnant women
• Implemented under the Universal Immunization Programme by Govt. of India
• Important vaccines for children:
• At birth: BCG, Hepatitis B, OPV
• 6,10,14 weeks: Pentavalent, OPV, Rotavirus,PCV
• 9-12 months: MR, JE in endemic areas
• 16-24 months: DPT booster, MR
• Tetanus toxoid or tetanus and diphtheria at early stages of pregnancy
• Vaccines are transported, stored and handled at optimal temperature also known as Cold Chain.
National Immunisation Schedule
Q7 Discuss some newer vaccines
mRNA Vaccines (COVID-19*)Pfizer-BioNTech (Comirnaty) and Moderna (Spikevax): They work by using messenger RNA to instruct cells to produce a protein
similar to the spike protein of the SARS-CoV-2 virus, prompting the immune system to recognize and fight the virus if exposed in the future.
****2) Respiratory Syncytial Virus (RSV) Vaccines**RSV is a common virus that causes respiratory infections, particularly severe in infants ,older
adults,&immunocompromised individual
Abrysvo (Pfizer) and Arexvy (GSK): Both of these RSV vaccines weredesigned to prevent severe RSV eg pneumonia
*3) Malaria Vaccine – RTS,S/AS01 (Mosquirix, *,* became the first malaria vaccine to be recommended by the World Health Organization (WHO) for wide use in
2021.Efficacy: RTS,S offers partial protection against malaria, reducing the risk of malaria by about 30-40% in children.
*4) Shingrix (Herpes ) Shingrix is a recombinant vaccine*, meaning it contains a protein from the herpes zoster virus to stimulate immunity, along with an adjuvant (a
substance that enhances the immune response).
 Q8 Discuss Covid 19 vaccines
• P zer biotech
• mRNA Vaccine
• Age groups: Individuals >16 years old
• Dose: 2 doses (0.3 mL each) 3 weeks apart
• Route : intramuscular
• Site: Deltoid muscle
• Covishield
• Individual >18 years old
• Intramuscular: Deltoid
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• Dose: 0.5 mL — 2 doses (4-12 weeks apart)
• Covaxin
• Whole virion inactivated ( BB152)
• Age group: individual >18 years old
• Route : intramuscular
• Site : Deltoid muscle
Q9 DNA and mRNA vaccines

DNA and mRNA vaccines use genetic material to instruct cells to produce antigens, triggering an immune response. Here's a brief overview:

DNA Vaccines:

Use plasmid DNA containing a gene for the antigen.

DNA is transcribed into mRNA in the cell nucleus, and the mRNA is translated into protein in the cytoplasm.

Antigen is presented via MHC molecules to activate T-cells and stimulate antibody production.

Delivered via injection or electroporation.

mRNA Vaccines:

Use synthetic mRNA encoding the antigen, delivered in lipid nanoparticles.

mRNA is directly translated into protein in the cytoplasm.

Antigen presentation triggers both humoral (antibody) and cellular (T-cell) immunity.

Avoids the nucleus, minimizing genome interaction.

Both mimic infection to elicit immunity, leveraging host cell machinery for rapid antigen production.
Q10 What are AEFIs?

• An adverse e ect following immunisation is de ned as any untoward medical

occurrence following immunisation which does not necessarily have a casual
relationship to the vaccine. The adverse event may be any unfavourable or
unintended sign, abnormal laboratory nding,symptom or disease.
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