Immunization Risks and Effects

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Questions and Answers

What is a characteristic of adenovirus when used as a viral vector?

Integrates into the host genome

Allows for high transgene expression (correct)

Can only infect non-replicating cells

Has low immunogenicity

Which viral vector is known for its low immunogenicity and long-term gene expression?

Retrovirus

Adenovirus

Adeno-associated virus (correct)

Poxvirus

What is a primary limitation of using retroviruses as viral vectors?

Limited packaging capacity

Random integration in host DNA (correct)

High immunogenicity and toxicity

Inability to infect dividing cells

What makes hybrid vectors advantageous in gene delivery?

They combine characteristics from multiple viral vectors Signup and view all the answers

Which viral vector is most commonly used for pediatric applications due to its high immunogenicity?

Sendai virus Signup and view all the answers

What is the primary feature of DNA vaccines?

They introduce a plasmid containing the DNA sequence encoding an antigen Signup and view all the answers

Which of the following components is NOT typically found in a DNA vaccine plasmid?

Replicating viral components Signup and view all the answers

Which mode of delivery is LEAST likely to be used for DNA vaccines?

Oral ingestion Signup and view all the answers

What is a potential advantage of DNA vaccines demonstrated in studies?

Induction of protective immunity Signup and view all the answers

What characteristic of DNA vaccines has shown improvement in recent studies?

Enhancement of immune potency Signup and view all the answers

What is considered the best potential delivery site for DNA vaccines?

Skin and mucosal membranes Signup and view all the answers

Which of the following types of vaccines does NOT include nucleic acids?

Live attenuated vaccines Signup and view all the answers

Which feature is essential for the functionality of a DNA vaccine?

In situ production of the target antigen Signup and view all the answers

What is the incidence rate of Vaccine-associated paralytic poliomyelitis (VAPP) for the oral polio vaccine?

1 in 2.7 million Signup and view all the answers

Which of the following reactions is most likely associated with the measles vaccine?

Thrombocytopenic purpura Signup and view all the answers

Which vaccine type is known to contain only isolated proteins of the pathogen?

Subunit vaccines Signup and view all the answers

What is a significant feature of polysaccharide vaccines?

They induce only short-term immunity. Signup and view all the answers

Which of the following is a complication of the whole-cell pertussis vaccine?

Hypotonic, hyporesponsive episodes (HHE) Signup and view all the answers

What was a significant milestone for polio eradication in India?

Declaration of polio-free status in 2014 Signup and view all the answers

Which component is primarily responsible for the immune response in protein-based subunit vaccines?

Isolated specific proteins Signup and view all the answers

What was a major reason for starting special polio campaigns in India in 1995?

To fulfill the resolution for global polio eradication Signup and view all the answers

What is one potential consequence of mRNA-based vaccine platforms?

Potent type I interferon responses Signup and view all the answers

In which decade were mRNA vaccines first discovered?

1960s Signup and view all the answers

What is a key characteristic of replication-defective viral vectors?

They have been modified to prevent lysis of the host cell. Signup and view all the answers

What is the primary purpose of using a live vector vaccine?

To transport pathogen pieces for immune stimulation Signup and view all the answers

Which year marked the beginning of clinical testing for mRNA vaccines?

2013 Signup and view all the answers

What modification enhances the translation of mRNA according to research?

Incorporation of pseudouridine Signup and view all the answers

Which aspect of vector vaccines contributes to their effectiveness?

They deliver antigen genes to target cells. Signup and view all the answers

How do replication-competent viral vectors differ from replication-defective ones?

Replication-competent vectors can cause host cell lysis. Signup and view all the answers

What is the primary function of the integration of sequences between LTRs in the context of lentiviral transfer plasmids?

To integrate viral genetic material into the host genome Signup and view all the answers

What is the purpose of a self-inactivating (SIN) configuration in lentiviral transfer plasmids?

To make the virus unable to produce any new viral particles after integration Signup and view all the answers

What is a major difference between monoclonal and polyclonal antibodies?

Polyclonal antibodies are derived from multiple B cell types Signup and view all the answers

Which characteristic is typical of fourth generation vaccines?

Incorporate advanced adjuvants for enhanced immunity Signup and view all the answers

In the context of vaccine development, what role do immunologically relevant molecules play?

They stimulate an immune response by mimicking pathogens. Signup and view all the answers

What is the main advantage of using a lentiviral vector in vaccine development?

It allows for permanent integration of antigens into host genomes. Signup and view all the answers

What is the primary function of an envelope plasmid in lentiviral vector systems?

To enable the virus to enter the host cells Signup and view all the answers

Which component of the immune response is specifically targeted by monoclonal antibodies?

A single, specific epitope on an antigen Signup and view all the answers

Study Notes

Oral Polio Vaccine

Vaccine-associated paralytic poliomyelitis (VAPP) occurs at a rate of 1 in 2.7 million vaccinations.
Vaccine-derived poliovirus (VDPV) includes circulating types known as cVDPV, with 750 confirmed cases reported to date.

Measles

Febrile seizures occur mainly in children under five years and are usually not fatal, affecting approximately 0.3% of vaccinated children.
Thrombocytopenic purpura has a reported incidence of 0.03%.
Anaphylaxis may result, predominantly due to vaccine components like sorbitol.

Inactivated Whole-Cell Vaccines

Examples include Inactivated Poliovirus Vaccine (IPV) and whole-cell pertussis vaccines.
The pertussis vaccine can cause hypotonic-hyporesponsive episodes (HHE) in approximately 1 in 4,762 doses.

National Polio Eradication in India

Over 60% of global polio cases were in India, which declared polio-free status on March 27, 2014.
The Sabin vaccine was developed in India in 1970.
India engaged in polio vaccination campaigns starting in 1995, following resolutions from the World Health Assembly since 1988.

Subunit and Polysaccharide Vaccines

Subunit vaccines contain only the antigenic components necessary to provoke an immune response.
They provide protein-based antigens and may require boosters due to uncertain long-term immunity.
Polysaccharide vaccines are less effective in infants and children under 18-24 months, offering only short-term immunity and slow antibody response.

Third Generation Vaccines

Approaches include introducing specific antigens or live attenuated infectious agents that do not cause disease.

Nucleic Acid Vaccines

Types include DNA and RNA vaccines, alongside vector-based and non-vector-based approaches.
DNA vaccines introduce plasmids encoding antigens into tissues and utilize various delivery methods (e.g., injections, gene guns).

Current Status of DNA Vaccines

Preclinical studies show promising protective immunity, with ongoing improvements in design and delivery to enhance immune response.

History of mRNA Vaccines

Discovered in the 1960s, with initial successful delivery into cells in the 1970s.
First mouse testing occurred in 1990, leading to clinical tests starting in 2013.

Vector Vaccines

Live vector vaccines utilize weakened viruses to transport pathogen pieces to stimulate immune responses.
Replication-defective vectors are often preferred due to their safety profile.

Types of Viral Vectors

Adenovirus: High immunogenicity and transduction rate; can infect non-replicating cells; no integration.
Adeno-associated virus: Long-term gene expression; can infect non-dividing cells; low immunogenicity.
Poxvirus: Capable of both replication-competent and replication-deficient strains.
Retrovirus: Can integrate genetic material into the host genome but risks tumorigenesis.

Antibodies as Vaccines

Monoclonal antibodies have specific advantages, while polyclonal antibodies provide broader responses.

Fourth Generation Vaccines

Concepts include soluble binary molecules or quaternary forms for immune enhancement.

Case Studies

SARS-CoV-2: Ongoing global vaccine development, focusing on immunological relevance.
Mycobacterium tuberculosis: Antigen 85 is a candidate for vaccine development against tuberculosis.

Extra Resources for Further Study

Various platforms available for more detailed information on vaccine science and development.

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Description

Explore the complexities of vaccination, focusing on the oral polio vaccine and its associated risks, such as Vaccine-associated paralytic poliomyelitis (VAPP) and vaccine-derived poliovirus. Additionally, learn about febrile seizures linked to measles vaccinations, particularly in children under five. Understand these health concerns to make informed decisions about immunization.