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Viruses mutate very quickly. As they move through a population, passing from individual to individual, they change to bypass the immune system defenses and environmental conditions and sometimes they just make random changes from imperfect replications. Many viruses will be almost completely genetically different from their parent or grandparent viruses.
The flu shot we get each year has been developed to contain the three types of currently active flu viruses determined by epidemiologists to be most likely spreading in the next flu season. These are rarely the same viruses year to year because the prior year's viruses have almost always mutated to new forms before they circle around again the following year.
When you get a flu shot, your body reacts and produces antibodies in the blood that fight off those particular flu viruses for life (in some circumstances, but in others the immunity does lessen over time). The problem is that each flu season brings a slightly (or greatly) changed flu virus that the last year's antibodies are usually not very effective in fighting.
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The flu vaccine is made based on what scientists think will be the next year's most active flu viruses. If they waited until the first flu cases, there would not be time to produce all the vaccine needed for millions of people. They study what viruses are circulating in other parts of the world to determine scientifically which are the most likely ones to hit during our next flu season. They make a pretty good forecast analysis.
This is also the reason that there is no cure for the common cold: there are 300-some different types of common cold viruses, and each of those can make slight changes (mutations) that make them unable to be recognized as the same by your immune system. Once you have had one of those, you may not ever catch that exact same cold virus again, but the changes and mutations occur often and quickly in the cold viruses, so it is close to impossible for your body to make new antibodies to defend itself against the newest versions or for your previously made antibodies to be close enough to work on the mutated viruses.
Because we need protection from newly created flu viruses which our past vaccinations were not developed to fight.
Influenza viruses are especially able to easily mutate into new forms and strains. Because of this, there is an almost constant creation of new flu viruses to infect humans, some we are susceptible to and some are not able to make us sick for one reason or another.
Each year in the US, the regular flu vaccine is developed to be able to protect us from the three most common types of flu viruses that are infecting people in other parts of the world at that time, and that are the ones that are expected to spread to the US in the following flu season. Because of the way seasonal flu spreads across the world, those viruses that are infecting people in the Eastern Hemisphere or Southern Hemisphere in the summer will be the most likely ones that will cause flu in the Northern and Western Hemispheres in our upcoming flu seasons in the fall and winter. Often the protection we got from the prior year's flu shot will not be effective against the newly created strains.
It is needed because there are probably something new -here let me explain
Pretend there is a virus that makes you vomit, make your head hurt..
If a person gets those symptoms a new symptom might appear like it makes you depressed or muscles hurt.
that's why they need to come up with new ones every year...
I hope this help you :D
Some change each year. There are different viruses developing all the time. The flu changes each year, so each year a new variation of the vaccination is required and people need to get it. In one sense the vaccination is not being repeated, as the vaccination is slightly different each year.
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Once you get the flu you are immune to getting it again?
No it changes that's why you need a new flu shot every year. Otherwise we would only need one and it would be done.
Is it necessary to get the Swine Flu shot every year?
That will only be needed if a new mutation of the swine flu occurs that the current swine flu vaccine isn't able to prevent. In the 2009-2010 flu season in the US two shots were need, the regular seasonal flu shot and the H1N1/09 Swine flu shot. But in the current 2010-2011 flu season in the US, the seasonal flu vaccination contains the vaccine for swine flu in addition to the other varieties of flu that are expected to be circulating. So only one shot is needed this year for protection in the flu season.
Why do doctors recommend that people get a flu shot each new flu season?
Because each season the flu shot contains a new range of flu virus strains to protect against that year's likely flu types. The types are continuously changing because a virus such as the influenza mutates quickly, making it difficult for the immune system to recognize and destroy the new strains, and necessitating a new vaccine.
What is the new way that you get the flu shot?
up your nose or with a patch.
Why Every year a new influenza vaccine is developed What is the most likely reason that doctors do not use the same vaccine each year?
Typically the flu vaccine is trying to predict the possible states of the flu coming for that season. The flu virus mutates so rapidly that they are always trying to predict what's coming next. That's why you can also still get the flu even if you get a flu shot. STUDY ISLAND ANSWER:The virus which causes influenza adapts each year to the last vaccine in order to survive and reproduce.
What are the causes to having the flu shot more than once?
I think you mean the effects of being vaccinated more than once? Some feel it may increase risks for multiple sclerosis, Guillain-Barré , and other autoimmune disorders, as well as type 1 diabetes in children. If you mean why were you administered more than one flu shot, there could be a number of reasons. Regular annual flu shot& H1N1 could be separate, it could be the 1st one was for different strains, then updated - thus getting another shot, could be the doctor or nurse that gave you the shot was unaware that you had already had the 1st one... If you're talking about why the shot is annual, different flu strains are prevalent, morph, and new types of flu are introduced every year.
Why is it possible to only be vaccinated once for measles but the flu vaccine is required yearly?
Oh, well for all intents are purposes, there is only one strain of the measles. One vaccinted you are vaccinated forever. (Depending on the vaccine, tetatnus is every 10 years.) But, there are thousands of strains of the flu. Once vaccinated you do stay vaccinated, but each year there are many, many brand-new flus. If you catch the flu you are immune to that strain forever too, which is why the old ones don't keep coming back. The flu vaccine is made to protect against the 3 or 4 that doctors predict will be the worse each season. It doesn't protect against them all and it can't protect against the new mutations that we will see next year. Hope this clears things up for you!
Vaccines against the flu are different every year why is this?
The flu virus constantly mutates, leading to new strains every year. Vaccine manufacturers update the vaccine annually to include the most prevalent strains, providing the best protection. This process helps ensure that the vaccine is effective against the specific flu viruses circulating each year.
Are you fully vaccinated after having one Swine Flu vaccination last year or do you need it annually?
One H1N1/09 "Swine Flu" vaccination was determined to be enough in the 2009 clinical trials of the brand new vaccine for the brand new virus. If you had the vaccination it will provide immunity for life to that particular virus. If the virus mutates into a strain that is much different from the one in the prior vaccine, then there may be a need for a new vaccine for the newly formed virus. So far, that has not happened. You need a seasonal flu shot annually because of the problem with the easy mutations of flu viruses. In the 2010-2011 flu season, the vaccine for the swine flu is included with the other vaccines in the seasonal flu vaccinations, so if you did not get the separate shot last year, this year you will get lifetime immunity from that exact type of flu in the "regular" flu vaccination. (It won't hurt and might help to get that vaccine again).
Does last year's flu shot still work?
It will work almost forever for the exact same flu viruses. However due to viruses' ability to mutate to new forms that would not be prevented by the injection you already had, you will need a new vaccine for the new mutated virus or other different flu viruses that the scientists have determined are likely to be the ones making people sick this year. Sometimes it is the same ones, but most often the strains of flu viruses do change each year and that is why a new shot is required before each new flu season and why each vaccination is for three different types of flu (called trivalent vaccines).This year the 2011-2012 seasonal flu vaccine in the US contains vaccines for these three different flu viruses:A/California/7/2009 (H1N1)-like virus; (the pandemic swine flu)A/Perth/16/2009 (H3N2)-like virus; andB/Brisbane/60/2008-like virus.* Note:The pandemic swine flu vaccine was also in the 2010-2011 flu season vaccine formulation, but it does not hurt to have a second dose (or if you took it also in 2009-2010, it is still okay to get this year's vaccine and, it might help some people).
What are the Ingredients of flushots?
Flu shots are weakened or killed viruses of the sort thought to be the principle carriers of the new year's flu. Flu viruses change, or mutate, rapidly, so you need a different mix every year. A very few people are allergic to some proteins acquired in the preparation process, usually from eggs. Others actually get the flu from the shots, but it's usually a mild case.
When is the last day of shot gun season in New York state?
The season dates are published every year in the game regulations.
