Immunization and Types of Immunity

Immunization

• Immunization is a critical component of disease prevention, reducing serious illnesses and deaths.
• Herd immunity is also an important outcome of effective immunization programs.
• The immune system recognizes foreign invaders (antigens).
• Macrophages and B cells have receptors to detect antigens.
• Immune cells, like T cells, break down antigens, exposing them to other immune cells.
• Cytotoxic T cells attack infected cells.
• Helper T cells activate other immune cells.
• B cells differentiate into plasma cells, producing antibodies that bind to foreign antigens.
• Antibodies or killer T cells reach the antigen and initiate the humoral or cellular response.

Types of Immunity

• Active Immunity: The body is exposed to a relatively harmless antigen, not causing infection. The body then produces antibodies.
• Passive Immunity: Antibodies are administered directly, not produced by the body's immune response. This can be through clinical administration of serum or concentrated immunoglobulins.
• Natural Active Immunity: A person develops immunity by surviving a prior disease, producing antibodies.
• Natural Passive Immunity: Antibodies are transferred from a mother to her baby through the placenta during pregnancy.

Purpose of Immunizations

• Key component of preventing disease
• Reduce serious illness and deaths
• Achieve herd immunity

How Vaccines Work

• Vaccines use weakened or inactive microorganisms to stimulate antibody production.
• The immune system recognizes these antigens as foreign invaders, triggering an immune response.
• Macrophages and dendritic cells engulf vaccine antigens, presenting them to T cells and B cells.
• Helper T cells activate B cells, leading to antibody production.
• Cytotoxic T cells attack infected cells.
• B cells multiply and produce more antibodies available if the same microorganism is encountered again.
• Memory cells are created, leading to a faster and stronger immune response if the body is re-exposed.

Types of Vaccines

• Live-attenuated vaccines use a weakened version of the virus to stimulate a strong antibody response. They usually produce immunity after one dose.

• Inactivated vaccines use a non-live vaccine that typically requires adjuvants and multiple doses to generate high and sustained antibody response.

• Vector Vaccines use genetic material from a specific virus placed in a different or modified virus. The modified virus instructs the body to create antibodies against the original virus.

• mRNA Vaccines use genetically engineered messenger RNA to get the body to replicate the S-protein found in a virus; this stimulates the body to create antibodies. mRNA then breaks down.

Population's Opinion and Common Myths

• Some common misconceptions relate to the presence of microchips, harmful ingredients, links to autism or Sudden Infant Death Syndrome (SIDS).
• Some believe that it is better for children to contract a disease to develop immunity (rather than getting vaccinated).
• Another common myth is that vaccines alter DNA.

Epidemiology and Immunization

• Epidemiology is important for determining prevalence, incidence, risk factors, at-risk groups, and the severity of diseases, including the measles.

Pre-Vaccine Information

• Assess the patient's health, including a complete history.
• Explain the vaccine benefits and risks.
• Assess any contraindications or precautions related to prior reactions.

Post-Vaccine Information

• Counsel vaccine recipients about reporting and management of common adverse events.
• Keep vaccine recipients under observation for at least 15 minutes after receiving a vaccine.
• Advise them to notify their doctor or healthcare provider about any concerns following vaccination.

Group Work

• Divide and choose a vaccine from the Canadian Immunization Guide.
• Describe the epidemiology of the disease the vaccine targets.
• Describe key points to teach the recipient or guardian.
• Describe any contraindications or who should not receive the vaccine.
• Discuss any related concerns or myths.

Vaccine Safety

• Public tolerance for vaccine side effects is low.
• Public lack of vaccine safety confidence threatens successful immunization programs.
• Vaccines offer lifelong benefits, while most side effects are minor and temporary.
• Rare serious reactions are tracked by public health authorities.

Vaccine Development

• Diseases are targeted for vaccine development.
• Thorough lab testing occurs and researchers conduct clinical trials in various phases.
• Ethical review is critical throughout the research.
• Continuous monitoring of vaccine safety is performed.

Vaccine Testing and Approval

• Health Canada examines results from clinical trials to assess if vaccines are safe, protective, and high quality.
• Quality assurance is vital in the manufacturing and storage steps, including constant manufacturing batch testing for quality and standards.
• Vaccines are carefully packaged and stored under controlled temperatures.

Vaccine Recommendations

• The National Advisory Committee on Immunization (NACI) reviews evidence related to a vaccine's best use for different populations.
• Public Health Agency of Canada approvals are followed by recommendations to healthcare providers.
• Provincial/territorial decisions are made regarding public access to vaccines; this often includes funding, availability at specific locations, e.g. pharmacies, schools.

Pandemic Planning

• Influenza pandemics tend to exhibit wide scale health problems.
• They cause waves of illness, deplete healthcare resources, and can overwhelm health care systems due to their wide scale.
• Pandemic plans are essential elements of quality assurance to properly handle any type of possible pandemic.
• Goal of pandemic planning is to minimize serious illness and deaths and limit societal disruption.

Pandemic Preparedness

• Pandemics differ in character but often feature characteristics that are significant.
• Pandemics tend to occur (and last) for more than 12-18 months, outside of typical seasonal flu.
• Several types of pandemics occur, and the strains/types may replace each other or dominate over certain seasons.

Aftermath of a Pandemic

• Reflecting on personal, educational and professional experiences over the COVID-19 pandemic
• Understanding lessons learned about pandemic planning, gaps in the healthcare system, and potential future impact on interprofessional skills

Assignment- Vaccine Debate

• Pro and con vaccination views.
• Understanding arguments and rationale for a given viewpoint.
• Evaluating safety and benefits of vaccination, and individual rights vs. the greater good.