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US Pharm. 2012;37(11):17-18.
A Seasonal Viral Infection
Influenza, often referred to as the “flu,” is a contagious
viral infection that circulates each year during the period from
October to May. Although a mild case of the flu might be mistaken for
the common cold, most cases have more severe symptoms beyond simply a
sore throat and nasal congestion. Influenza symptoms usually last 7 to
10 days and include fever, chills, body aches, headache, cough, and
fatigue. Bed rest and plenty of fluids are general treatment
recommendations, along with OTC medications aimed at relieving symptoms.
A vaccine is available to help protect against influenza
by stimulating the production of antibodies to flu viruses. The viruses
that cause the flu can change each year, so a vaccine is formulated
every year to offer specific protection during the upcoming flu season.
The current trivalent influenza vaccine includes protection against
three specific strains of viruses: one strain of influenza A (H3N2), one
strain of influenza B, and another strain of influenza A (H1N1),
commonly known as “swine flu.”
Everyone 6 months of age and older should receive the flu
vaccine each year as soon as it is available. It takes 2 to 4 weeks
after vaccination to build effective immunity against the flu. It is
especially important for certain groups of people to receive the flu
vaccine because they are at higher risk for developing serious
complications. These groups include people 65 years and older; those
with chronic diseases such as asthma, lung disease, or diabetes;
pregnant women or those who may become pregnant or breastfeed during the
flu season; and those who take care of people at high risk for serious
complications from the flu.
The Flu Vaccine Is Recommended for Those Aged 6 Months and Older
Although influenza is considered a nuisance by most,
thousands of people in the United States die each year from the flu or
related complications. Most of those deaths are in people 65 years and
older, but even younger, healthier people can become seriously ill from
the seasonal flu. For these reasons, everyone 6 months of age and older
should receive the flu vaccine each year, unless they are allergic to
chicken eggs or the vaccination itself, or have a history of
Guillain-Barré syndrome (a paralytic reaction) after a previous
influenza vaccination.
Getting Vaccinated to Prevent the Flu
The flu vaccine is made from the killed virus strains most
likely to be circulating in the upcoming flu season. There are four
methods of administering the flu vaccine, with specific guidelines for
their use in certain patient groups. These include the standard
intramuscular flu shot, a high-dose shot for people 65 years and older,
and an intradermal shot using a much smaller needle for people ages 18
to 64 years. There is also a nasal spray formulation made from live but
weakened flu virus strains that do not cause the flu but result in
immunity against the viruses included in the vaccine. The nasal
formulation is approved only for healthy, nonpregnant people ages 2 to
49 years who do not have asthma or a history of wheezing. If you need to
be vaccinated for the seasonal flu, many pharmacies provide this
service.
Treatment of Flu Symptoms
Symptoms of the flu can resemble the common cold, which is
also caused by viruses. In addition to the sore throat, runny nose, and
nasal congestion typically seen with a cold, a person suffering from
influenza can have a fever or feel feverish, with body aches, headache,
fatigue, and a cough. Young children with the flu may feel nauseated or
have diarrhea. Although any of these symptoms can accompany the common
cold, people with influenza are more likely to have more symptoms and
feel more ill than those with a cold.
The goal of treatment is to ease symptoms and speed
recovery while avoiding complications. General recommendations include
bed rest and drinking plenty of fluids. Acetaminophen or nonsteroidal
anti-inflammatory drugs (NSAIDs such as ibuprofen or naproxen) can
relieve fever, headache, and body aches. Decongestants, cough
suppressants, and expectorants are useful for cough and congestion. Many
nonprescription cold or flu symptom relievers contain multiple drugs,
so it is important to read the labels to avoid taking more than the
recommended dose of the same medication in two or more products. There
are also antiviral medications approved for prevention and/or treatment
of influenza that reduce the severity of symptoms, shorten the period of
illness, and help prevent complications. Antivirals carry a warning
that they are not to be used as a substitute for the vaccine, as they
may not be protective against all influenza viruses.
Complications likely to develop from the flu include
bronchitis, pneumonia, and sinus or ear infections. These complications
are often caused by bacteria and should be treated with an antibiotic.
If symptoms of influenza begin to improve and then worsen, a bacterial
infection may be the cause and the patient should seek medical care for
evaluation.
To comment on this article, contact rdavidson@uspharmacist.com.
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