What are vaccines for influenza made from?

Answer 1

If the influenza vaccine is to be made from a live virus, then the strain is selected, grown, and then weakened (usually chemically) to be able to trigger an immune response but not be strong enough to cause the infection. If it is to be made using a "dead" or inert virus that also does the same to trigger immune response and antibody production without causing infection, then the virus is grown and then made inactive before being used in the vaccine.

Once the virus particles needed are produced one of the two ways above, they are purified, isolated and combined with administration medium that is either for injection or for use with a mist/inhalation administration medium.

There are sometimes adjuvants added that will make a little go a long way (these are not used in the US flu vaccines). This way smaller doses are needed and so more vaccine can be distributed to more people in shorter times. This is helpful if the strain is not easily or quickly grown and vaccine is needed quickly.

There are also preservatives added to maintain the purity of the vaccine. This is needed especially in multi-dose vials that are not used entirely upon opening of the sterile vials. Single dose vials and syringes are usually available without the addition of these preservatives for people with special needs or Allergies to the preservatives.

For a full list of the common ingredients used today in flu vaccines, see the related question below about the specific ingredients in the swine flu vaccine.

Answer 2

If the influenza vaccine is to be made from a live virus, then the strain is selected, grown, and then weakened (usually chemically) to be able to trigger an immune response but not be strong enough to cause the infection. If it is to be made using a "dead" or inert virus that also does the same to trigger immune response and antibody production without causing infection, then the virus is grown and then made inactive before being used in the vaccine.

Once the virus particles needed are produced one of the two ways above, they are purified, isolated and combined with administration medium that is either for injection or for use with a mist/inhalation administration medium.

There are sometimes adjuvants added that will make a little go a long way (these are not used in the US flu vaccines). This way smaller doses are needed and so more vaccine can be distributed to more people in shorter times. This is helpful if the strain is not easily or quickly grown and vaccine is needed quickly.

There are also preservatives added to maintain the purity of the vaccine. This is needed especially in multi-dose vials that are not used entirely upon opening of the sterile vials. Single dose vials and syringes are usually available without the addition of these preservatives for people with special needs or Allergies to the preservatives.

For a full list of the common ingredients used today in flu vaccines, see the related question below about the specific ingredients in the swine flu vaccine.