Biomedical Sciences: Prevention of Viral Infections (Lecture 9; Exam 2)

True/False: Antiviral treatments are readily available and reliable to treat viral diseases.

False.

Ways to prevent viral infections:

• Good public health measures

• Proper nutrition

• Effective personal hygiene

  • Hand hygiene

• Immunization (Vaccination)

  • Herd immunity

• Attention to infection control procedures

What is the best defense against viruses?

Vaccinations.

What is adaptive immune response?

A slow, highly specific defense system that targets specific pathogens and creates long-lasting immunological memory.

What is immune memory?

The immune’s system’s ability to quickly recognize a germ or foreign substance it has seen before and launch a faster, stronger defense.

Why should we vaccinate?

• To prevent severe disease and death.

• To protect those at most severe risk (babies, elderly, etc.)

• To prevent disease entirely

• Decrease sources for transmission (herd immunity)

• To prevent infection entirely

Types of Immunization:

• Active

• Passive

What is active immunization?

Generates immune memory.

(immune response stimulated because of challenge with an exposure to immunogen.)

What is natural active immunization?

Exposure to infectious agent. (infection)

What is artificial active immunization?

Exposure to microbes or antigens in vaccines.

What kind of protection does active immunization create?

Long-term immunization.

What is passive immunization?

Purified, antibody or antibody-containing serum to provide rapid, temporary protection or treatment of a person.

What is natural passive immunization?

Newborns receiving natural passive immunity from maternal immunoglobin that crosses placenta or is present in mother’s milk.

What is artificial passive immunization?

Injection of antibody or serum.

(i.e. HBV, Rabies, VZV, Tetanus)

What kind of protection does passive immunization create?

Short-term protection. (Protection passes)

Active Immunization

Putting pathogen or pathogen parts into someone to stimulate their immune system (induces immune memory).

• Natural: Infection

• Artificial: Vaccines

Passive Immunization

Putting products of immune response (e.g. antibodies) into a recipient (no memory, passing immunity)

• Maternal antibodies - Breast milk

• Artificial - Injection of immune serum (i.e. rabies Ig, convalescent plasma)

What type of immunization are vaccines?

Artificial active.

Vaccine Types:

1. Live, attenuated (replication-competent)

2. Inactivated (replication-incompetent)

***do not confused active/passive immunization with inactivated vaccines***

What are live, attenuated vaccines?

A weakened form of pathogen that generally CANNOT cause disease but can replicate. (mild or unnoticed disease)

What are inactivated vaccines?

Unable to replicate, but retains immunogenicity of pathogen or toxin.

True/False: Inactivated vaccines are able to replicate.

FALSE.

(But they retain immunogenicity of the pathogen or toxin.)

True/False: Live, attenuated vaccines are able to replicate.

TRUE.

Types of Inactivated Vaccines:

• Inactivated whole agent vaccine

• Toxoids (Diptheria, Tetanus)

• Subunit vaccines

  • Recombinant vaccines

  • Virus-like particle (VLP) vaccines

• mRNA Vaccines

• Polysaccharide vaccines

• Viral Vector Vaccines

What are recombinant vaccines?

Subunit vaccines produced by genetically engineered microorganisms.

• (FluBlok, HBV)

What are virus-like (VLP) vaccines?

Empty capsids.

• (HPV, Future influenza vaccines)