What is the flu shot?
The flu shot is a vaccine given with a needle, usually in the arm. The seasonal flu shot protects against the three or four influenza viruses that research indicates will be most common during the upcoming season.
Is there more than one type of flu shot available?
There are several flu vaccine options for the 2014-2015 flu season.
Traditional flu vaccines made to protect against three different flu viruses (called “trivalent” vaccines) are available. In addition, flu vaccines made to protect against four different flu viruses (called “quadrivalent” vaccines) also are available.
Trivalent flu vaccine protects against two influenza A viruses (an H1N1 and an H3N2) and an influenza B virus. The following trivalent flu vaccines are available:
- Standard-dose trivalent shots (IIV3) that are manufactured using virus grown in eggs. Different flu shots are approved for people of different ages, but there are flu shots that are approved for use in people as young as 6 months of age and up. (Most flu shots are given with a needle. One flu vaccine also can be given with a jet injector, for persons aged 18 through 64 years.)
- An intradermal trivalent shot, which is injected into the skin instead of the muscle and uses a much smaller needle than the regular flu shot. It is approved for people 18 through 64 years of age.
- A high-dose trivalent shot, approved for people 65 and older.
- A trivalent shot containing virus grown in cell culture, which is approved for people 18 and older.
- A recombinant trivalent shot that is egg-free, approved for people 18 years and older.
The quadrivalent flu vaccine protects against two influenza A viruses and two influenza B viruses. The following quadrivalent flu vaccines are available:
- A quadrivalent flu shot.
- A quadrivalent nasal spray vaccine, approved for people 2 through 49 years of age (recommended preferentially for healthy* children 2 years through 8 years old when immediately available and there are no contraindications or precautions).
(*“Healthy” in this instance refers to children 2 years through 8 years old who do not have an underlying medical condition that predisposes them to influenza complications.)