mjl1717
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antigenic shift
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| Microteacher
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It's really more likely to be because of the antigenic drift, i.e., when slightly different variants come around each flu season. An antigenic shift would mean a sudden massive change in the virus composition (and I would guess that isn't something that even the vaccine manufactuers could predict!).
Decisions for the composition of the vaccine for the 2005-2006 flu season will be made next month (February); it's always a bit of a gamble because they have to make a "guestimate" as to what's going to be prevalent.....
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| docshah
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I read that they use the three most prevelant strains in the past year and use that as the Flu SHot for the coming season. This is why there is a new flu shot every year due to the Antigenic Shift mentioned above.
I might be wrong but this is what i can recalll. Cheers! :idea:
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| docshah
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Although I got the flu shot, I got the flu twice! Go Figure! :oops:
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| bactitech
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Did you truly have influenza - fever, headache, bad respiratory symptoms? Was this substantiated by testing? Usually true flu has sudden onset and you feel like total CRAP and have to go to bed.
Vomiting and diarrhea usually is not indicative of true influenza. That's not to say it isn't viral, but is not influenza. Type A usually has more severe symptoms.
BTW, we're not getting a lot of rapid influenza testing in from our ER this year. Last year during December we were totally swamped, with a lot of positives for A.
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| mjl1717
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Is that correct ? Do we use different vaccines for the flu because of antigenic DRIFT and not antigenic shift? Do you agree with that?
{P.S. In pure slang- This is your barbecue over here .}
For the forum: This how I remember it- minor change drift, I drift my car into another lane/ major change shift, if I shift my car I may be making a U turn 
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| bactitech
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My theory is rusty - I've been out of school for 30 years. I'll leave that up to you guys to figure out. :-)
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| Alina T
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antigenic drifts are the ones hapenning every year, and necessitate new vaccines.
shifts can happen too with influenza, but these are rare, and thats when they cause pandemics.
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| niti
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"milu" wrote:
Why do we need different vaccines for the fllu?
Two types of flu vaccines:
1) flu shot—an inactivated vaccine containing killed virus.. is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions.
2) Nasal-spray flu vaccine—a vaccine made with live, weakened flu viruses that do not cause the flu (sometimes called LAIV for “Live Attenuated Influenza Vaccine”). LAIV is approved for use in healthy people 5 years to 49 years of age who are not pregnant.
Each vaccine contains three influenza viruses—one A (H3N2) virus, one A (H1N1) virus, and one B virus. The viruses in the vaccine change each year based on international surveillance and scientists’ predictions about which types and strains of viruses will circulate in a given year.
antigenic shift:
Sudden change in mole. str. ( RNA/DNA) which is responsible for new strains…true for influenza virus, associated with large scale epidemics.
antigenic drift:
change in antigenicity..common in HIV….that’s why its difficult to make effective HIV vaccine.
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