Lecture 16 Flashcards
what is influenza
known as the flu, highly contagious infection of the airways caused by influenza viruses
Influenza type A characteristics
Potentially severe illness
humans and animals
epidemics and pandemics
influenza type B characteristics
usually less severe illness
humans only
epidemics alone
antigednic drift
gradual change in the rna of the virus, slight changes in the sequence, causes vaccine mismatch but not complete zero
antigenic shift
drastic shift, vaccinated individuals may not have immunity. how pandemics arise
when does influenza A start and peak
late oct start, peak jan or later
when does influenza B peak
march, because influenza A happens first, followed by a smaller B season
which age groups see more influenza
less than 5, over 65
direct effects: respiratory
asthma and COPD exacerbations
ear/sinus infections
bronchitis and pneumonia
indirect effects: multi-organ Systems
TRIGGER: MI, Ischemic heard disease, CV disease
EXACERBATION: hypertension, renal disorder, diabetes
How does influenza cause acute MI
All the inflammation that the virus causes results in stimulation of cytokine system, interleukins, tnf factors. Cause inflammation in the systemic system. Causes plaque formation, rupture, which causes MI or stroke because of that.
why are adults 65+ at greater risk
immunosenescence - natural and progressive weakening of the immune system over time
results in higher risk and severity of infection diseases
less responsiveness to vaccines
mode of transmission
droplets - coughing or sneezing, travel up to 2 meters’ in distance
Contact transmission - droplets contaminate surfaces or objects, can survive up to 48h on hard, non porous surfaces
incubation time influenza
the time period from exposure to development of symptoms is about 1 to 3 days, average 2
three most common influenza symptoms
cough, fever, myalgia
gold standard for diagnosis
viral culture, takes 3-10 days to get results
common in practice diagnosis
Rapid influenza diagnostic test
not very accurate
when should antivirals be initiated
within 48 hours or less of onset of symptoms for max effectiveness, not often seen in practice
neuraminidase inhibitor MOA
are the drug of choice - prevent N protein of virus from detaching itself and being released into the host tissue
Three N inhibitors
oseltamivir (tamiflu, oral)
recommended drug of choice
zanamivir,(relenza, inhaled product)
Peramivir IV, used for very sick hospitalized patients
what have RCT showed in terms of NI
can reduce duration of illness by approx 30 hours
reduce the severity of illness by 35hours
NI effect in hospitalized patients
improved survival, even if taken after 48hour time limit
did not improve duration of hospitalization
whats the rec?
give antivirals as early as possible for pts with confirmed or suspected individuals that are hospitalized, has severe complicated progressived illness or higher risk of influenza complications
dosing of oseltamivir
75mg one cap twice a day for 5 days
zanamivir dosing
10mg (2inh) bid for 5 days
periamivir dosing
600mg IV for 30 minutes, one day
ADR in oseltamivir
primarily in children:
- abnormal behaviour
- delirium
- hallucinations
- agitation
- N/V
Zanamivir counselling
signs of an allergic reaction - hives, difficulty breathing, swelling of your face, lips, tongue or throat
drug interactions with antivirals
LAIV
- live vaccine, thus antivirals will stop viral replication because it is an antiviral. do it either 2 weeks before or 48 hours after
when to use chemoprophylaxis
prevention of inf in persons with HR of influenza following vaccination after exposure to a person with inf
prevention for ppl at HR for comp from influenza or Health care workers that cannot receive inf vaccine
residents of LTCF when there is an outbreak in the facility
what flu vaccine do you use for most of the pop
GSK
products for seniors
FLUAD and FLuzone
vaccine for kids
FLumist, nasal spray
who is LAIV CI for
severe asthma
children 2-7 on aspirin
children less than 24 mo
pregnant woman
persons with immune compromising conditions
