Vaccines

natural passive immunity

immunity acquired from antibodies passed in breast milk (IgG) or placenta (IgA)

natural active immunity

immunity gained through illness and recovery

artificial passive immunity

immunity gained through antibodies harvested from another person or animal

artificial active immunity

immunity acquired through a vaccine

passive immunities

antibodies transferred from an outside source

active immunities

you create the antibodies

immunotherapy

• used as a prophylactic (prevent disease after exposure to a pathogen) measure

• used to treat active infection

• ex. antitoxin, convalescent serum, and Ig

• used for:

  • patients at risk for rapidly fatal diseases (rabies)

  • patients at risk for bacterial diseases with exotoxin (diphteria, botulism, tetanus)

  • patients who are immunodeficient (HIV, chemo)

how vaccines elicit a long term immune response

• act as pathogen imposters

• contain a dead or attenuated pathogen that stimulate the immune system to produce antibodies or cytotoxic T cells

• develop memory cells that confer future protections

• develop immunity to the disease without having to get the disease first

attenuated vaccines

use live/active but weakened pathogens

inactive vaccines

unable to replicate and cause infection

1. inactivated/killed agent

2. subunits

3. toxoid

4. conjugate

5. DNA/RNA

6. vector

adjuvant

substances that enhance the effectiveness of a vaccine

a benefit of using an inactivated vaccine over live attenuated vaccine

no risk of causing infectious disease

antibody response of attenuated vaccines

robust

antibody response of inactivated vaccines

robust

cell mediated immunity (CMI) of attenuated vaccines

good

cell mediated immunity (CMI) of inactivated vaccines

poor

duration of protection of attenuated vaccines

long term

duration of protection of inactivated vaccines

short term

number of doses for attenuated vaccines

usually single

number of doses for inactivated vaccines

multiple

risk of reversion to virulence for attenuated vaccines

very low

risk of reversion to virulence for inactivated vaccines

none

attenuated vaccine risk to immunocompromised and pregnant patients

can be significant

inactivated vaccine risk to immunocompromised and pregnant patients

none

storage stability for attenuated vaccines

poor

storage stability for inactivated vaccines

good

inactivated whole agent vaccines

use killed whole cells or inactivated whole viruses

subunit and conjugate vaccines

use key protein antigens or antigenic fragments from a pathogen

• contain polysaccharides (capsules) linked to proteins

• polysaccharides (T-independent = weak) need to be conjugated to enhance antigenicity in young children and increase strength of immune response

toxoid vaccines

contain inactivated exotoxin (toxin is modified to no longer have toxicity but still retain antigenic epitopes)

DNA/RNA vaccines

inject pieces of pathogen’s genetic code

vector vaccines

use a chemically weakened virus to transport pieces of the pathogen’s genetic code

herd immunity

higher the immunization rate in a population, the less likely an infectious agent can spread due to insufficient susceptible hosts

populations unable to be immunized

• immunocompromised (AIDS patients, patients taking immunosuppressive drugs/chemo)

• pregnant women

• elderly or babies

reproductive # (R0)

the number of people, on average, that one infected individual spreads the infection to

overloaded immune system misconception

DEBUNKED by…

our immune system is fully capable of being exposed to many pathogens at a time and does so naturally all of the time, so it is safe to receive multiple vaccinations at once

disappeared diseases misconception

DEBUNKED by…

diseases are only rarely seen or “gone” due to vaccinations and herd immunity, that does not mean you do should not stop getting vaccinated, the diseases still exist

more vaccinated than unvaccinated people get sick misconception

DEBUNKED by…

more people overall are vaccinated, meaning that pure numbers agree, but is a misleading claim; those vaccinated have a less intense infection response when sick

natural immunity is better than vaccine acquired immunity misconception

DEBUNKED by…

vaccines give weak/dead pathogens so there is no risk of infection, natural immunity carries more risk during active infection than artificially acquired immunity

compare risk of vaccine vs risk of the disease

potential adverse effects of vaccines

• local soreness at injection site

• mild fever

• malaise

• feeling tired

rare potential adverse effects of vaccines

febrile seizures - convulsions in young children associated with high fever

anaphylaxis - allergic reactions to chemicals other than the antigen which may be present in the preparations