What is Flu Vaccine?
The standard flu shot vaccine is made from flu viruses that have been grown on fertilized chicken eggs. The viruses are killed during manufacturing, a process known as “inactivation.” These inactivated viruses provide proteins or antigens that trigger a protective antibody response when the vaccine is injected into the arm or thigh muscle. Antibodies against flu viruses begin to appear one to two weeks after getting the flu shot and last for months, and sometimes even up to one year.
Important Note: The standard flu shot is the main flu vaccine that will be offered at facilities in the Sutter Health network for the 2016 to 2017 season. The Centers for Disease Control and Prevention (CDC) does not recommend the intra-nasal flu vaccine FluMist for this season, therefore we will not be offering this vaccine.
Two other flu vaccines will also be available to certain patients:
- Fluzone High-Dose: This flu vaccine has four times the antigen dose compared to the standard flu vaccine, and is approved only for people 65 or older.
- Flublok: This is a recombinant flu vaccine manufactured without the use of eggs. It is indicated for people 18 years or older who are highly allergic to eggs. It is available only in our Allergy Departments.
Sutter care centers have transitioned from trivalent to quadrivalent flu vaccines (containing two A strains and two B strains) with the exception of Fluzone High-Dose and Flublok, which are still trivalent (two A strains and one B strain). The second B strain was added to quadrivalent vaccines by manufacturers because predicting which flu B strain would circulate in any given season proved difficult. While this is a modest change, scientists hope it will result in increased protection against the flu in coming years. The higher dose of antigens in Fluzone High-Dose vaccine produces higher antibody levels in patients 65 years or older which results in a modest boost in effectiveness compared to the standard-dose vaccine.
Because vaccine strains often change from one year to the next and immunity wanes, flu vaccine must be given every year.
All flu vaccines in the Sutter Health network are free of thimerosal and latex.