KN

Lecture 19

Vaccine Hesitancy

  • Definition: Reluctance or refusal to vaccinate despite the availability of vaccines.

  • Aristotle’s Persuasion Elements:

    • Trustworthy messenger
    • Sense-making arguments
    • Emotional connection
    • A worthy goal for the messenger
  • Strategies to Address Vaccine Hesitancy:

    • Patient-Provider Interactions:
    • Listen and respect concerns
    • Build common ground
    • Be honest about vaccine imperfections
    • Diversity in Healthcare:
    • Increases trust when healthcare professionals reflect the community's diversity
    • Transparency in Healthcare:
    • Reducing private industry influence and being clear about relationships with pharmaceutical companies.

Diagnostic Tools of Immunology

Immunoprecipitation

  • Definition: A serology technique used to measure small soluble antigens based on the dependence of antigen-antibody ratios.
  • Concepts:
    • Antigen Excess: When there is too much antigen relative to antibody.
    • Antibody Excess: When there is too much antibody relative to antigen.
    • Equivalence: The optimal ratio where the number of antigenic sites equals the number of antibody-binding sites.

Agglutination

  • Definition: A method to measure insoluble antigens on whole cells through cross-linking.
  • Applications:
    • Blood Typing: Mixing patient blood with known antibodies to detect clumping, indicating a positive reaction.
    • Pathogen Identification: Adding antibodies to pathogens to observe clumping, confirming the presence of specific antigens.

Enzyme-Linked Immunosorbent Assay (ELISA)

  • Functionality:
    • Detects either antibodies or antigens in samples.
  • Types:
    • Direct ELISA:
    • Detects pathogen antigens directly in the patient’s sample.
    • Involves immobilizing antigen to a plate and using enzyme-linked antibodies for detection.
    • Indirect ELISA:
    • Detects antibodies against a pathogen using a known antigen on the assay plate to capture patient antibodies.
    • Requires that antibodies have formed, meaning that it is best used for past infections.
    • Sandwich ELISA:
    • Involves capturing antigen using a specific antibody and detecting it with a secondary antibody conjugated to an enzyme.
  • Limitations:
    • High levels of antigen required for direct ELISA.
    • Indirect ELISA may not work for recent infections due to the time needed for antibody production.

Importance of Clinical Microbiology

  • Purpose:
    • Identifying the infectious agent of disease is crucial for effective treatment and prevention of complications.
  • Key Reasons:
    • Guide antibiotic treatment based on susceptibility.
    • Prevent antibiotic resistance, e.g., Neisseria gonorrhea resistance to penicillin.
    • Surveillance of epidemiological outbreaks.
  • Steps for Identification:
    • Collect specimens based on signs/symptoms, medical and travel history, and knowledge of local outbreaks.
    • Use clinical tests for pathogen identification, including biochemical methods and serological assays.

Specimen Collection

From Sterile Areas

  • Types of Samples:
    • Blood, cerebrospinal fluid (CSF), pleural fluid, synovial fluid, and internal organ tissues.
  • Key Procedures:
    • Blood cultures: Collected via venipuncture, careful to avoid contamination.
    • CSF: Obtained through lumbar puncture, requiring sterile techniques.

From Nonsterile Areas

  • Types of Samples:
    • Throat/nasopharynx, sputum, stool, skin lesions, and deep wounds.
  • Techniques:
    • Sterile swabs for throat cultures, special mediums for transport, and using selective media to inhibit normal microbiota growth in cultures.

Mpox (Monkeypox)

Overview

  • Caused by: Monkeypox virus (MPXV), an enveloped dsDNA virus from the Poxviridae family.
  • Current outbreak: Notable for the IIb subclade.

Transmission and Symptoms

  • Transmission:
    • Through broken skin, mucous membranes, or maternal to fetal transmission.
  • Symptoms:
    • Fever, sore throat, headaches, muscle pain, lymphadenopathy;
    • Characteristic skin lesions evolving from flat bumps to blisters.

Complications

  • Risk factors include:
    • Young children, pregnant women, and immunocompromised individuals.
  • Potential complications:
    • Secondary infections, pneumonia, sepsis, encephalitis, and possible death.

Treatment and Prevention

  • Treatment:
    • Supportive therapy is crucial.
    • Monitoring of high-risk individuals.
  • Prevention:
    • Vaccination for those at high risk or after exposure.
    • Strict hygiene practices including isolation of symptomatic patients.