Download Influenza - Shoreview Pediatrics

Vaccines
Influenza
The signs are everywhere. Get your flu shots. Shoo the flu. Why?
Misconceptions vs Facts about Influenza Immunization and
Children
Misconception- Influenza is not a serious disease.
Fact- Influenza is a highly contagious, significant respiratory infection that each year
causes tremendous morbidity and mortality in our country and throughout the world.
In the U.S., an average of 226,000 hospitalizations per year are related to influenza. Of
these admissions, approximately 20,000 hospitalizations were children. Nearly half of
these were children under 6 months of age, and 80% of the total were children less than
2 years old. Complications resulting in hospitalization include pneumonia, respiratory
failure, uncontrolled asthma, myocarditis, and exacerbations of their chronic health
condition.
In August 2010, the Centers for Disease Control and Prevention (CDC) reported
that the average annual death rate from influenza in the U.S. is about 23,000, but ranged
from as low as 3000 to nearly 50,000 deaths over the last 30 years.
Misconception- I don't need to get vaccinated, because I never get the flu.
Fact- Consider yourself lucky.
Influenza activity typically peaks from December to March in temperate climates,
but may occur earlier or later. Influenza occurs throughout the year in tropical areas.
Each year, worldwide 3 million to 5 million people suffer from influenza, with an annual
mortality rate of 200,000 to 500,000. During the 2009 H1N1 pandemic, an estimated 1.8
million to 5.7 million cases of influenza occurred in the United States alone.
Influenza causes significant illness. The incubation period varies from 1-4 days,
and the severity of the illness depends on prior influenza experience and the circulating
strain of influenza. "Classic" influenza disease is characterized by the abrupt onset of
fever, significant body aches, sore throat, nonproductive cough, headache and rhinitis.
The fever is usually 101-102 degrees, but can be as high as 104. Systemic symptoms
and fever typically last 2-5 days.
Most people recover from influenza without serious outcomes, but not everyone.
Adults over 50 years of age and individuals with immunosuppressive conditions suffer
the most complications and also mount the least protective antibody levels with the
influenza vaccine. By vaccinating yourself, you decrease the chance of spreading the
infection to the most susceptible individuals in the community.
Misconception- The vaccine is not meant for healthy children.
Fact- Individuals with the highest risk of illness and hospitalization are children less
than 6 months of age and children and adults with underlying health problems, such as
asthmatic, respiratory, immunosuppressive, cardiovascular, metabolic or neurologic
disorders.
However, evidence supports that healthy school-aged children typically have the
highest attack rates and are responsible for much of the influenza transmission in a
given season. While adults can transmit influenza from the day before the onset of
symptoms to approximately five days after symptoms begin, children are contagious
longer and can transmit disease for more than ten days. Influenza also has a substantial
impact on school-aged children and their contacts. These impacts include school
absenteeism, medical care visits, spreading the illness to siblings, and parental work
loss. Therefore, experts believe universal vaccination of school-aged children will
reduce transmission in the community, prevent disease in high risk adults and children,
reduce the costs associated with influenza, and interrupt influenza outbreaks.
As a result, starting in the 2008-2009 influenza season, the Advisory
Committee on Immunization Practices (ACIP) recommended that all children aged
6 months to 18 years receive annual influenza vaccines. In addition, this year the
ACIP recommends universal influenza vaccination for all Americans 6 months of age
and older.
Misconception- The vaccine is not suitable for young children.
Fact- Presently, there are two forms of influenza vaccine available- the trivalent
inactivated influenza vaccine (TIV) and the live attenuated influenza vaccine (LAIV).
The TIV or traditional "flu shot" is approved for individuals 6 months and over, and the
LAIV or "flu mist" is approved for healthy, non-pregnant persons from 2 through 49
years of age.
Misconception- The vaccine is not effective.
Fact- Efficacies achieved with the LAIV and the TIV can be as high as 90% and 65%
respectively. Studies show that the LAIV induces a longer period of immunity, can be
given as soon as it becomes available in the summer, and may provide some immunity
the following year, even if the circulating strain is different than the previous year's
vaccine. The TIV level of protection can wane by the end of the influenza season, so
"flu shots" are not started until the TIV is available in September and must be repeated
each year.
Misconception-The vaccine causes the flu.
Fact- Influenza is not “the stomach flu” or a bad cold, and placebo controlled studies
have shown that the influenza vaccine does not cause influenza illness.
Misconception- I got a flu shot and still got influenza.
Fact- Influenza is not “the stomach flu” or a bad cold; however, sometimes the influenza
vaccine is not a perfect match with the circulating strain of influenza.
Seasonal influenza illness is caused by influenza A and influenza B. Influenza A
viruses are prone to mutations, and influenza B is slightly more stable. Authorities keep
constant record of the multiple strains that are circulating globally, and each year
vaccines are developed in anticipation of the three strains of influenza [A(H1), A(H3)
and B] that will most likely be in circulation during the coming influenza season. After
production of the seasonal vaccine begins, however, a different strain may become the
predominant strain. This mismatch will affect the efficacy of the influenza vaccine given
that year, and a vaccine recipient could develop a mild to moderate case of true
influenza. This mismatch has less impact with the LAIV.
The 2009 H1N1 pandemic was caused by a major mutation in an influenza A
strain. Because the antigenic shift occurred after the seasonal vaccine production started,
a separate monovalent H1N1 vaccine had to be developed, tested, and produced. Once
individuals began receiving the separate H1N1 vaccine, the spread of novel influenza
decreased dramatically.
Misconception- If I get influenza, I'll just get an antiviral medication.
Fact- Though antiviral medications are available to decrease the severity of an
influenza illness, resistance to the antiviral medications has become an increasingly
worrisome issue, as well as the side-effects of the preparations.
Prevention is the key to managing influenza. Minimizing the spread of influenza
and other respiratory illnesses during the respiratory season is essential. Wash your hand
or use liquid sanitizers frequently. Stay at least 3-6 feet away from sick people. Avoid
touching your eyes, nose and mouth, especially without washing your hands first. Avoid
sharing food, drinks or personal items with others. Avoid crowded gatherings or
settings. If you are sick, cover your mouth and nose with a tissue or your upper sleeve,
whenever you cough or sneeze. Stay home until you are symptom free. Use a facemask
if you must be around other susceptible individuals. Use a humidifier to increase
humidity, as influenza viruses thrive in dry air. Get an influenza vaccine.
Diagnosis is established through clinical grounds or through laboratory testing.
High fever, body aches and cough, when influenza is circulating in the community, is
highly suggestive of influenza with a positive predictive value of 80%. Laboratory
confirmation, through antigen tests or cultures, can be performed on mucosal swabs
from the nasopharynx, but sensitivity and specificity vary with the test used and the
circulating strain.
Once a person is diagnosed with influenza the main management is supportiverest, fluids, antipyretics and time. Antipyretics, including acetaminophen and ibuprofen,
reduce fever, body aches and sore throat and subjectively make the patient feel better.
Aspirin products should be avoided because of the risk of developing Reye's syndrome.
If significant respiratory symptoms develop, medical care should be obtained
immediately.
Influenza antiviral preparations can be effective in reducing the degree and the
length of illness in an affected person, but their effectiveness is highly time and age
dependent and is complicated by the emergence of resistant strains. There are currently
four antivirals available- amantadine, rimantadine, oseltamivir and zanamivir. To be
beneficial, the antiviral must be initiated within 36-48 hours of onset of symptoms. The
strain of influenza must be determined, and the age and health conditions of the patient
are considerations of whether the antiviral can be used. Antivirals can be used
prophylactically in highly susceptible individuals. Non-judicial use of antivirals
increases the development of influenza resistance.
Adapted from:
1. the CDC website- Influenza
2. Epidemiology and Prevention of Vaccine Preventable Diseases, 11th editionInfluenza
3. Wisconsin Medical Journal August 2010 issue-fighting the flu: what we've
learned about H1N1 and more
4. Vindico Medical education November 2008 issue- Universal Influenza Vaccination
Strategies
Updated 10/12/10