Lecture 12 Flashcards
Vaccine Efficacy & Effectiveness
Antigen
foreign substance (virus, bacteria, toxin)
Antibody
what your body makes in response to antigens
Titer
presence and amount of antibodies in blood (how much antibody you have in your blood)
Cold Chain
coordinated events in temperature-controlled environments to store, manage, and transport vaccines (allows vaccines to stay stable)
- temps too high or too low = decrease potency
Passive Immunity
develops after you receive antibodies from someone or somewhere else – not in your antibody
Passive Immunity: Two types
- Natural - antibodies received from mother to baby
- - breastmilk, via placenta (baby receives antibody through mom) - Artificial - antibodies received from medicine or infusion
- - monoclonal antibodies (mAbs), immunoglobulins (IVIG)
Passive Immunity: Advantages & Disadvantages
Advantages - provides rapid and immediate protection (gets active antibody quick)
Disadvantages - short duration, expensive to manufacture, may not protect against new variants
Active Immunity
occurs when exposure to a disease organism triggers the immune system to produce antibodies to that disease
Active Immunity: Natural & Artificial
Natural - antibodies developed in response to an infection (when body encounters disease & gets antibodies)
Artificial (vaccine induced) - antibodies developed in response to a vaccination
Active Immunity - Advantages & Disadvantages
Advantages - long lasting
Disadvantages - slow to develop (takes about 2 weeks to build up immunity)
body is making its own antibodies
Vaccine Type: Live Attenuated
Antigen - weakened form of the disease-causing pathogen
Vaccine Type: Inactivated
Antigen - killed version of the disease-causing pathogen
Vaccine Type: mRNA
Antigen - mRNA that corresponds to a protein on the surface of the pathogen
Vaccine Type: Subunit, Recombinant, Polysaccharide, & Conjugate
Antigen - use specific pieces of the disease-causing pathogen–sugar, protein, or capsid
Vaccine Type: Toxoid
Antigen - toxin made by the disease-causing pathogen–create immunity to the parts of the pathogen that cause a disease instead of the pathogens itself
Vaccine Type: Viral Vector
Antigen - dont contain antigens, instead use the body’s own cells to produce them by using a modified virus (the vector) to deliver genetic code or antigen
what is VFC?
Vaccines for Children - government program which covers the costs of vaccines for eligible children
herd community
- protecting those who cannot get vaccinated
- significant portion of the population is immune against disease, limiting the spread
- provides indirect protection
- level needed depends on the disease
herd community - criteria
- disease agent must be restricted to a single host species
- transmission must be relatively direct from one individual to another
Basic Reproductive Number
R naught is the expected number of secondary cases produced by a single infection in a completely susceptible population
if R0 < 1 then disease will die out
if R0 = 1 then disease is endemic
if R0 > 1 then disease will spread
R naught equation
= (number of contacts per unit time) x (transmission probability per contact) x (duration of infectiousness) = cpd
what does CPD stand for in R0 equation?
c = average rate of contact between susceptible & infected people
p = probability of infection given contact between. susceptible & infected individual
d = duration of infectiousness
calculation the critical vaccination level (Vc)
- proportion of the population that must be vaccinated to achieve herd immunity
Vc = 1-(1/R0))
Threshold % = Vc x 100
Assumptions:
- vaccination takes place at random
- assumes 100% vaccine effectiveness
Vaccine Efficacy
- refers to how the vaccine performs in ideal conditions (controlled clinical trials)
VE = (ARU - ARV) / (ARU) x 100
ARU = B/(B+D)
ARV = A/(A+C)
