Influenza vaccine FluBlok has been approved for people 18 to 49 years old who have anaphylaxis or other serious reactions to any vaccine components that contain certain antibiotics, egg proteins or latex.
FluBlok also does not contain any preservatives, such as thimerosal, a harmful mercury derivative.
After clearance by the Food and Drug Administration, the new vaccine was licensed in January by Protein Sciences Corp. FluBlok is quite different in that it is made without eggs and without using any actual influenza virus. Currently, most flu shots are created with different strains of influenza developed in eggs, which can trigger allergic reactions in some cases.
Using an egg to cultivate a flu virus is a lengthy process. After weeks of virus gestation inside the embryo, the virus is extracted and incapacitated. Because they are months-long in the making, most flu shots are made from strains from the previous year’s flu season.
Viral strains thought to be in force each year are inoculated and then incubated in millions of fertilized chicken eggs. After the virus has grown, the eggs are opened, and the virus is extracted and then purified by a chemical treatment that effectively “kills” the virus by rendering it into an inactive protein.
Each final dose of flu vaccine is very small, containing only fifteen millionths of a gram of each of the different viral strains chosen for that year.
FluBlok has altered the process to be egg-free, and is only the second eggless flu vaccine on the market.
The vaccine is produced by recombining the DNA of a germ called baculovirus, which commonly infects insects. A protein called hemagglutinin, or HA, is then produced in response to the germ. HA is the vehicle protein that allows the flu virus to replicate in human cells. Since FluBlok actually contains no virus, it is thought to be better overall for allergy sufferers and for those who develop side-effects to flu shots.
For more information on FluBlok, see the FDA package insert.
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