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Influenza Vaccine Information

During flu season, an annual flu vaccine is the best way to reduce the chances that you get seasonal flu and lessen the chance that you spread it to others.  When more people get vaccinated against the flu, less flu can spread through the community.

The 2019-2020 influenza vaccines will be available in two formulations: trivalent or quadrivalent.  Trivalent vaccines protect against the influenza A/Brisbane/02/2018 (H1N1)pdm09-like, influenza A/Kansas/14/2017 (H3N2)-like, and influenza B/Colorado/06/2017-like (Victoria lineage) virus.  In addition to the three components in the trivalent vaccine, the quadrivalent vaccine also contains influenza B/Phuket/3073/2013-like (Yamagata lineage) virus.

A flu vaccine is needed every year because flu viruses constantly change over time.  The flu vaccine is formulated each year to keep up with flu viruses as they change.  Also a yearly flu shot is needed because a person’s immune protection from being vaccinated decreases after a year, and yearly vaccination provides the best protection against the flu through the entire flu season.

The CDC recommends that people get vaccinated against flu as soon as the 2019-2020 flu vaccine becomes available in their community and continue throughout the flu season.  Influenza seasons are unpredictable and can begin as early as October.  For a list of available vaccine options available during the 2019-20 season, click here.
The CDC recommends that everyone six months of age and older get vaccinated each year.  It is especially important for certain people, who are at higher risk of having complications or who are in close contact to those at higher risk, to be vaccinated for flu.

These people include:

  • Children aged 6 months to 4 years
  • People 65 years of age and older
  • Women who are pregnant or will be pregnant during flu season
  • People of any age with certain chronic medical conditions such as asthma, chronic lung disease, kidney disorders, liver disorders, neurological and neurodevelopment conditions, blood disorders, endocrine disorders (such as diabetes mellitus), metabolic disorders, or heart disease (not including high blood pressure)
  • People who have a weakened immune system due to disease or medication (such as people with cancer, HIV or AIDS, or those on chronic steroids)
  • Children aged 6 months to 18 years who are receiving long-term aspirin therapy, and may be at risk for Reye syndrome after flu infection
  • People who are morbidly obese (body-mass index is 40 or greater)
  • People who live in nursing homes and other long-term care facilities
  • American Indians or Alaska Natives
  • People who live with or care for those at high risk for complications from flu, including:
    • Health care workers  
    • Household contacts of persons at high risk for complications from the flu
    • Household contacts and out of home caregivers of children less than 6 months of age (since these children are too young to be vaccinated)

Vaccine Fact Sheets and Resources 


 Aqui No Hay Influenza 

OSDH Immunizations Information

External Resources