Oh, dear, nor am I a micro-biologist, but the short answer is that they have to make a different vaccine (or set of vaccines) each year, depending on the strains of virus that are around. Perhaps one of the others can help with a long answer.
From what I understand it takes a bit of educated guessing, so they have an idea of what flu it might be based on previous seasons and also through lots of testing of people currently with a flu (like human guinea pigs). Separate vaccines are then developed for flu seasons in the northern and southern hemishperes.
It says: “The shot, which is normally given in the arm, is made up of three different viruses. The three strains are chosen by scientists working in laboratories around the world. They collect flu viruses and predict which strains will be most prevalent in the coming flu season. The viruses in the shot are inactivated, or dead, which means that they can’t actually give you the flu.
But if your body remembers the virus, why do you need to get a flu shot every year? First, because flu strains differ from year to year; and second, because immunity declines over time.”
There is a lot of hard work that scientists have to do to figure out which strains of the flu are going to cause the biggest problems in any given year, and then they make the vaccine specifically for that strain (or those few strains). It is similar to what scientists do when they track any disease — if they can sequence the genome of the microorganism, they can figure out how it changes over time and either predict what changes might happen next, or what changes have happened most recently, and therefore the order in which the disease spread from one person to another.
Oh, dear, nor am I a micro-biologist, but the short answer is that they have to make a different vaccine (or set of vaccines) each year, depending on the strains of virus that are around. Perhaps one of the others can help with a long answer.
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From what I understand it takes a bit of educated guessing, so they have an idea of what flu it might be based on previous seasons and also through lots of testing of people currently with a flu (like human guinea pigs). Separate vaccines are then developed for flu seasons in the northern and southern hemishperes.
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@shannon212
Hello! I’m not an immunologist, BUT, I found a great summary on this site:
http://science.howstuffworks.com/life/cellular-microscopic/flu6.htm
It says: “The shot, which is normally given in the arm, is made up of three different viruses. The three strains are chosen by scientists working in laboratories around the world. They collect flu viruses and predict which strains will be most prevalent in the coming flu season. The viruses in the shot are inactivated, or dead, which means that they can’t actually give you the flu.
But if your body remembers the virus, why do you need to get a flu shot every year? First, because flu strains differ from year to year; and second, because immunity declines over time.”
0
There is a lot of hard work that scientists have to do to figure out which strains of the flu are going to cause the biggest problems in any given year, and then they make the vaccine specifically for that strain (or those few strains). It is similar to what scientists do when they track any disease — if they can sequence the genome of the microorganism, they can figure out how it changes over time and either predict what changes might happen next, or what changes have happened most recently, and therefore the order in which the disease spread from one person to another.
0