Page 1 | 2Influenza Vaccine

Visit the Utah Vaccination Locator to find a flu vaccine clinic near you.

Types of Influenza Vaccine

There are three types of influenza vaccines: an injectible shot; an intradermal (under the skin) vaccine and a nasal spray vaccine. Each season three strains of virus are included in the influenza vaccine; two type A viruses and one B virus. For the quadrivalent vccine, an additional B virus virus is included.

Vaccine manufacturers estimate 138-145 million doses of influenza vaccine will be produced for the U.S. market the 2014-2015 season. An estimated 30 million to 32 million doses will be quadrivalent flu vaccine. The rest will be trivalent flu vaccine.

Inactivated Influenza Vaccine or IIV - The inactivated influenza shot contains killed virus. Influenza shots are approved for use in people 6 months and older, including healthy people and people with chronic medical conditions. There are different types of the influenza shots available, including a high-dose vaccine for people 65 years of age and older. The high-dose vaccine is not recommended for people who have had a severe reaction to the influenza vaccine in the past.

The intradermal influenza vaccine is approved for people 18-64 years of age. The intradermal vaccine is injected into the skin instead of the muscle.

Live Attenuated Influenza Vaccine or LAIV - The nasal spray vaccine or LAIV contains the same three virus strains but are weakened live viruses. LAIV is approved for use in healthy people 2-49 years of age who are not pregnant.

Quadrivalent Influenza Vaccine - The quadrivalent influenza vaccine is designed to protect against four different influenza viruses; two influenza A viruses and two influenza B viruses. There is a standard-dose quadrivalent shot that can be given to children as young as 6 months of age. Other standard-dose quadrivalent shots are approved for people 3 years and older. The standard-dose quadrivalent nasal spray vaccine is approved for healthy people 2 through 49 years of age.

Influenza Vaccine Virus Strains

The World Health Organization (WHO) recommended that the Northern Hemisphere's 2014-2015 seasonal influenza vaccine contain the following three vaccine viruses:

  • A/California/7/2009 (H1N1)-like virus
  • A/Texas/50/2012 (H3N2)-like virus;
  • B/Massachusetts/2/2012-like (Yamagata lineage) virus.


Quadrivalent influenza vaccines will contain these antigens, and also a B/Brisbane/60/2008-like (Victoria lineage) virus.

Influenza Vaccine Recommendations

For a summary of 2014-2015 influenza vaccine recommendations, visit the Centers for Disease Control and Prevention (CDC).

Inactivated Influenza Vaccine (IIV) - injectable

Age Group Number of Doses
6 months - 8 years*
2
greater than 9 years
1

 

High-Dose Influenza Vaccine

Age Group Number of Doses
65 years and older
1

 

Intradermal Influenza Vaccine

Age Group Number of Doses
18-64 years
1

 

Live Attenuated Influenza Vaccine (LAIV) - nasal spray

Age Group Number of Doses
2-8 years with no previous influenza vaccine
2 separated by 4 weeks
2-8 years with 1 dose seasonal
influenza vaccine (See Notes 1, 2, 3)

1
9-49 years
1

 

Quadrivalent Influenza Vaccine - injectable

Age Group Number of Doses
6 months - 8 years*
2
9+ years
1

 

*Note: Influenza Vaccine in Children 6 months through 8 Years of Age

Children aged 6 months through 8 years who are receiving influenza vaccine for the first time, and some in this age group who have previously been vaccinated, require two doses of vaccine administered ≥4 weeks apart. Two approaches for determining the number of doses are recommended, both of which are acceptable.

1. The first approach, outlined in the flowchart (Figure 1), takes into consideration only doses of seasonal influenza vaccine received since July 1, 2010. This approach has the advantage of simplicity, particularly in settings in which it is difficult to ascertain vaccination history prior to the 2010-11 season. Using this approach, children 6 months through 8 years of age need only 1 dose of vaccine in 2013-14 if they received a total of 2 or more doses of seasonal vaccine since July 1, 2010. Children who did not receive a total of 2 or more doses of seasonal vaccine since July 1, 2010 require 2 doses in 2013-14.

2. In settings where adequate vaccination history from prior to the 2010-11 season is available, the second approach may be used. By this approach (Figure 1, footnote), if a child 6 months through 8 years of age is known to have received at least 2 doses of seasonal influenza vaccine during any prior season, and at least 1 dose of a 2009(H1N1)-containing vaccine--i.e., 2010-11, 2011-12, or 2012-13 seasonal vaccine or the monovalent 2009(H1N1) vaccine--then the child needs only 1 dose for 2013-14. Using this approach, children 6 months through 8 years of age need only 1 dose of vaccine in 2013-14 if they have received any of the following:

  • 2 or more doses of seasonal influenza vaccine since July 1, 2010 or;
  • 2 or more doses of seasonal influenza vaccine before July 1, 1010 and 1 or more doses of monovalent 2009(H1N1) vaccine or;
  • 1 or more doses of seasonal influenza vaccine before July 1, 2010 and 1 or more doses of seasonal influenza vaccine since July 1, 2010.


Children 6 months through 8 years of age for whom one of these conditions is not met require 2 doses in 2014-15.

3. While the influenza shot and the nasal spray vaccine both protect against the influenza, there is evidence that the nasal spray vaccine may work better in younger children than a regular influenza shot. CDC now recommends the nasal spray vaccine for healthy children 2-8 years when it is available.

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