Block 9 - part 2 Flashcards
Intervention strategies for HIV/AIDS
Blood donor screening, promotion/distribution of condoms, peer education for high risk groups, promotion of safe sex, diagnosis and treatment of STDs, HIV voluntary counselling and testing
Determinants of effective outcomes of intervention
Economics, priorities, setting
Current problems and issues surrounding HIV/AIDS intervention
Africa struggles against debt, trade restrictions and inadequate aid provisions,
global fund under-resourced,
US politics are retrogressive and harmful
7 PH objectives of vaccination
Reduce mortality and morbidity from vaccine preventable infections, Prevent outbreak/epidemics, Contain infection in a populations, Redue number of infections, Interrupt transmission to humans, generate herd immunity, eradicate infectious agent
9 factors influencing utility of vaccination for disease prevention
Disease burden risk of exposure age, health status, vacc Hx special risk factors reactions to previous vaccine risk of infecting othrs cost other ways to control? impact on public perception
3 things required for disease to be eradicated using vaccination
No other reservoirs of infection exist in animals or environment,
consequences of infection are very high,
scientific and political prioritisation exist
2 diseases which have been eradicated with vaccine
smallpox
polio
Herd immunity
level of immunity in population which protects whole population
what does herd immunity only apply to
Diseases which are passed from person to person
what is R0
Basic reproduction rate
Basic reproduction rate =
average number of individuals directly infected by infectious case during the infectious period, in a totally susceptibe population
factors affecting R0
rate of contacts in host population, probability of infection being transmitted during contact, duration of infectiousness
Effective reproduction rate (R)
estimates average number of secondary cases per infectious cases in a population made up of both susceptible and non susceptible hosts
Equation for effective reproduction rate
R=R0x
x=fraction of host population which is susceptible (50% - x=0.5)
R>1
Number of cases increases
R<1
number of cases decreases, needs to be maintained for elimination
R=1
Epidemic threshold
Equation for herd immunity
H = (R0-1)/R0
What is a susceptible population
Any person who is not immune to a particular pathogen