Module 5 - Population Health Flashcards
What are some host factors that affect disease?
- age
- gender
- genetics
- behaviours
- exposures
- immunity
What are some agent factors that affect disease?
- pathogenicity
- infectivity
- immunogenicity
- infective dose
What are some environmental factors that affect disease?
- social (crowding)
- physical (barriers, climate)
List 3 things that the objectives of an immunization program depend on
1 - availability and efficacy of vaccines
2 - capacity to reach target populations
3 - epidemiology of disease
What are 3 possible objectives of an immunization program?
1 - eradication of disease
2 - elimination of disease
3 - control of disease
Define: latency
time from infection with an infectious agent to the minimum level to transmit the disease
Define: incubation period
the time from exposure to the causative agent until the first symptoms develop (this is characteristic for each disease agent)
Define: symptomatic period
time from when the patient displays symptoms to the point when they have ended
Define: Infectiousness
Proportion of exposed persons who become infected
Define: Pathogenicity
proportion of infected people who develop clinical disease
Define: Virulence
proportion of people with clinical disease who become severely ill or die
Describe the spread of a disease
Once exposed, a person is either infected or not infected
Once infected, there is either disease or no apparent disease
Once sick, there is either a severe disease or not severe disease
What is herd immunity?
when the vaccinated portion of the population provides protection to unprotected individuals
What is the basic reproductive rate or R0?
number of secondary cases generated from a single infectious case introduced into a susceptible population
If R0 > 1 ……?
disease will increasingly spread (epidemic)
If R0 = 1 ….?
disease will stabilize (epidemic)
If R0 < 1 ….?
disease will disappear
If R0 = 15, how many people need to be immunized using herd immunity to prevent the disease becoming epidemic?
1 - 1/R0
1-1/15 = 0.94
so 94% of the population needs to be immunized to be able to protect the rest of the population (i.e. herd immunity)
What are some economic barriers to vaccines?
- cost of the vaccine
- time away from work for vaccine administration
- accessibility to immunization and immunization professionals
What are some system-based barriers to vaccines?
- increasingly complex immunization schedules
- different schedules across Canada
- inadequate documentation
- lack of a unique immunization record
- absence of standing orders
- inadequate tracking of immunization delay
What are some socially-related barriers to vaccines?
- lack of education of immunization providers and/or recipients
- inadequate communication of the complications of vaccine-preventable diseases
- increasing focus on the potential adverse effects of immunizations
