Influenza (Flu)

Below is information gathered from the CDC, AAP, and other health authorities to provide a summary of Influenza and why it is so important to be vaccinated against this annual threat. For more information, click on the links to the source material where applicable: 

Why get vaccinated?

During the 2013-’14 influenza season, 108 pediatric deaths were reported in people less than 18 years of age. Of these deaths 60% occurred in children and adolescents at high-risk because of underlying comorbidities, while 40% of pediatric deaths occurred in children with no recognized health problem. Approximately 90% of the children who died had not been vaccinated against influenza.

Because antibody concentrations fall to approximately 50% of peak levels 12 months after vaccination, annual vaccination is necessary even when vaccine composition does not change.

AAP NEWS Vol. 35 No. 12 December 1, 2014 

Although children with certain conditions are at higher risk of complications, substantial proportions of seasonal influenza morbidity and mortality occur among healthy children.” In fact, the rate of hospitalization for children under 2 years of age is higher than the hospitalization rate for the elderly over age 65 years.

PEDIATRICS Volume 132, Number 4, October 2013

What is it?

A respiratory virus that can cause moderate to severe illness and complications. Because of the virus’ ability to mutate constantly (drift), annual flu vaccination is necessary to prime the body’s immune system to recognize the current circulating strains.

How long is it contagious?

Most healthy adults may be able to infect others beginning 1 day before symptoms develop and up to 5 to 7 days after becoming sick. Children may pass the virus for longer than 7 days. Symptoms start 1 to 4 days after the virus enters the body. That means that you may be able to pass on the flu to someone else before you know you are sick, as well as while you are sick. Some persons can be infected with the flu virus but have no symptoms. During this time, those persons may still spread the virus to others.

Who is at high risk for medical complications due to Influenza?

  • All children aged 6 through 59 months (Children younger than 2 years are at an increased risk of hospitalization and complications attributable to influenza).
  • All persons aged ≥50 years;
  • Adults and children who have chronic pulmonary (including asthma) or cardiovascular (except isolated hypertension), renal, hepatic, neurological, hematologic, or metabolic disorders (including diabetes mellitus);
  • Persons who have immunosuppression (including immunosuppression caused by medications or by HIV infection);
  • Women who are or will be pregnant during the influenza season;
  • Children and adolescents (aged 6 months–18 years) who are receiving long-term aspirin therapy;
  • Residents of nursing homes and other long-term care facilities;
  • American Indians/Alaska Natives;
  • Persons who are morbidly obese (BMI ≥40).

Available Vaccine Products and Indications

A variety of influenza vaccine products are available, including either an inactive trivalent (2 stains of influenza A and 1 strain of influenza B) or inactive quadravalent (2 strains of both influenza A and B). All formulations of the live attenuated Flu mist are quadravalent (2 strains of both influenza A and B).  For many vaccine recipients, more than one type or brand of vaccine may be appropriate within indications and ACIP recommendations. Where more than one type of vaccine is appropriate and available, no preferential recommendation is made for use of any influenza vaccine product over another.

Timing of Vaccination

Who should or should not receive Flumist?

Flumist is indicated for healthy, non-pregnant persons aged 2-49 years. Individuals who care for severely immunosuppressed persons who require a protective environment should not receive FluMist given the theoretical risk of transmission of the live attenuated vaccine virus

Contraindications to LAIV include a severe allergic reaction to any component of the vaccine (requiring medical intervention), concomitant aspirin therapy, pregnancy, egg (ovalbumin) allergy, age less than 2 years, an episode of wheezing in the past 12 months for children 2 through 4 years, receipt of antiviral medication within the previous 48 hours or severe immunosuppression requiring a protective environment.

Precautions for LAIV vaccine include moderate to severe illness (until illness resolves), history of Guillain-Barré syndrome within six weeks of a dose of influenza vaccine, asthma in a person 5 years of age or older or any medical condition that might predispose to higher risk of complications (chronic pulmonary or cardiovascular disease, renal, hepatic, neurologic hematologic or metabolic disease). Severely immunosuppressed persons who require a protective environment should not receive LAIV and should avoid contact with LAIV recipients for seven days after vaccination.