Vaccination and Immunity

Vaccination is a form of active artificial immunity.
Approximately 500,000 infectious disease deaths occur annually in developed countries.
About 18 million infectious disease deaths happen each year in less-developed countries.

Acquired when an antigen stimulates the Immune Response (IR).
- Natural Active Immunity: Occurs when an individual has the disease and the immune response reacts to it.
- Artificial Active Immunity: Occurs when a vaccination stimulates the immune response.

Involves preformed antibodies being given to an individual.
- Natural Passive Immunity: Transfer of immunoglobulins (Ig) across the placenta or through breast milk to the infant.
- Artificial Passive Immunity: Injection of pre-formed immunoglobulins, such as gamma globulin.

Natural Immunity: Immunity acquired through natural processes, such as infections.
Artificial Immunity: Immunity gained through medical interventions, primarily through vaccinations.
Active Immunity: Immunity developed after exposure to an antigen, either through infection or vaccination.
Passive Immunity: Short-term immunity obtained from the transfer of antibodies.

Refers to the overall susceptibility of a population to infectious diseases.
Vaccination can enhance herd immunity, leading to a decrease in susceptible individuals in a community.
A decline in a population's vaccination status can increase overall susceptibility to diseases.
An individual’s immune status can influence their reaction to vaccinations and infections.

Vaccination: It involves artificial active immunization using specific antigens from an organism.
Vaccine Requirements:
- Must be safe.
- Must induce the correct immune response (humoral or cellular).
- Should promote a long-lasting specific immune response without causing the disease.
- Adjuvants: Substances that enhance the body’s immune response to the vaccine, often allowing for slower release and prolonged interaction with immune cells.
Vaccination schedules vary by country and depend on whether diseases are endemic.

Primary Response: Involves initial immunization leading to the generation of memory cells and antibodies.
Secondary Response: A faster and more robust immune response upon re-exposure to the antigen.
Memory cells play a vital role in maintaining immunity over time.

Passive immunization offers short-term immunity, while active immunization generally leads to long-term immunity.
Boosters may be required for active immunization to maintain protective levels of antibodies.

The levels of various immunoglobulins (Ig) in the serum of a newborn child post-birth are as follows:
- IgG Levels: Approx. 60% of adult levels at birth, increases to 800 mg/1000 ml by month 12.
- IgM Levels: Reach about 75% of adult levels by 12 months.
- IgA Levels: Not detectable at birth, grow significantly post-exposure.

Live Vaccines:
- Live Natural: Example includes Vaccinia for Monkeypox.
- Live Attenuated Vaccines: Weakened pathogens that mimic actual infections (e.g., Measles, Mumps, Rubella).
Killed Vaccines: Pathogens that have been killed using chemical or heat processes.

Subunit/Acellular Vaccines: Composed of parts of the microbe.
Recombinant Vaccines: Antigens produced via genetic modification (e.g., Hepatitis B).

DNA Vaccines: Contain plasmids carrying genes for antigens; stimulate an immune response within the body.
Human cells uptake DNA and express microbial proteins that elicit immune responses.

Developing vaccines is often less profitable than developing medicines.
Innovations include the use of plants for vaccines, oral vaccines, and reverse vaccinology methodologies.

Vaccines save approximately 2.5 million lives each year.
From 1994-2013, vaccinations are estimated to have prevented 732,000 early deaths in the U.S.

Historical data indicates a dramatic decrease in the number of cases of childhood infectious diseases upon vaccination (e.g., polio, measles).
Specific figures illustrate a decline in the incidence of diseases post-vaccination introduction from 1950 to 2000.

The HPV vaccine is a subunit vaccine that uses virus-like particles to prevent cervical, anal, and other cancers.
Types of HPV vaccines include Gardasil and Cervarix.

Analysis of recent outbreaks indicates the importance of vaccination in preventing disease; specific cases from 2001-2014 demonstrate outbreak patterns, particularly in measles.

Vaccines are considered the safest and most effective preventive method.
Possible side effects: symptoms reflecting immune activation (e.g., inflammation, fever).
Specific vaccines (e.g., live vaccines) have contraindications for vulnerable populations (e.g., pregnant women, immunodeficient individuals).
There has been misinformation regarding vaccine safety (e.g., discredited studies linking vaccines to autism).

Common reasons for not vaccinating include philosophical or religious beliefs and missed opportunities for vaccination.

Many infectious diseases currently have no vaccines available due to complex factors such as rapid antigenic variation in viruses (e.g., HIV), and misinterpretations in immune response for certain bacteria and protozoa.