Influenza (a.k.a. "the flu") Virus
Alida Merritt, MSN, RN, CPHQ
Quality Improvement/Infection Control
Marcus Daly Memorial Hospital
Hamilton, MT 59840
Influenza (a.k.a. "the flu") Virus
Influenza (a.k.a. "the flu") is a contagious respiratory illness
caused by influenza viruses and is most commonly spread by droplets. When
an infected person talks, sneezes, or coughs, they produce droplets containing
the virus. These droplets can travel up to 6 feet, landing on the mucous
membranes of nearby people. These droplets may also land on surfaces or
objects, and can be picked up on the hands of another person, who then
touches their eyes, nose or mouth. Once the virus contacts your mucous
membranes, it infects the nose, throat and lungs.
Within 1-4 days of exposure to the virus, you may experience any or all
of the following signs and symptoms: fever or feeling feverish, chills,
a sore throat, cough, runny or stuffy nose, muscle or body aches, a headache
and feeling extremely fatigued. Some people have equated having influenza
with "being hit by a truck." These symptoms may last as long
at 10-14 days and may be so severe that a person may be bed-bound (or
couch bound) for much of that time. An estimated 50-80% of people may
be infected with the virus, but not have symptoms; thus they are spreading
the illness to others without realizing it.
Anyone can get influenza, even those who are very healthy. Serious health
problems and complications can happen in association with influenza. In
the United States, an average 226,000 people are hospitalized and 36,000
die from influenza and influenza-related complications yearly. Certain
people and age groups have a higher risk of developing more serious influenza-related
complications, including younger children, people ?65 years, women who
are pregnant and people with certain chronic medical conditions. These
chronic medical conditions include asthma, COPD/emphysema, chronic heart
disease, diabetes, a weakened immune system due to disease or medications,
such as someone receiving chemotherapy or someone on chronic steroids,
as well as people with extreme obesity. Complications may include sinus
and ear infections, pneumonia, myocarditis (an inflammation of the heart),
encephalitis (an inflammation of the brain), rhabdomyolysis (inflammation
of the muscle tissues), as well as sepsis and multi-organ failure.
Sometimes it can be difficult to distinguish influenza from other viral
or bacterial illnesses based on symptoms alone. If your medical provider
wants to know for sure if you have influenza, he or she can perform a
specific test called the rapid influenza diagnostic test. This requires
a swab to be inserted deep into your nasal cavity and results are usually
available within 30 minutes. In some instances, your rapid test result
may be negative but your symptoms indicate otherwise, and so your healthcare
provider may still decide to treat you with antiviral medications. Sometimes,
when there is an influenza outbreak in a community, healthcare providers
will use their clinical judgment and treat infected people without performing
an influenza test.
Certain prescription medications known as "antiviral drugs"
are a treatment option for influenza. There are three FDA-approved influenza
antiviral medications for use during this flu season: Tamiflu, Relenza
and Rapivab. These antivirals are not available over the counter; you
must have a prescription from your healthcare provider to get them. These
medications may help lessen the severity and length of influenza symptoms,
and although they work best when started within 2 days of getting sick,
they may still help if started later. These antivirals may help prevent
some of the serious complications in people at higher risk.
Influenza is usually more prevalent during the colder months of the year,
and while influenza in the United States typically occurs between September
and May, the peak month is February. The single most important way to
prevent influenza is by getting a flu vaccination every year. The Centers
for Disease Control and Prevention (CDC) recommends that anyone 6 months
and older get an annual flu vaccine. Benefits of the influenza vaccine
are many, and include that it can help prevent the flu; it can reduce
the severity and length of illness if you do get sick; it can reduce the
risk of complications and influenza-related hospitalizations; it helps
protect women during and after pregnancy with some antibodies passed on
to the baby and providing some protective benefits for several months
after birth; and it protects those around you, especially those who are
more vulnerable to influenza and its complications.
One question asked by many people is, "How well does the vaccine
work?" Vaccine effectiveness varies from year to year, and depends
on the age and health of the person being vaccinated as well as how well
the vaccine "matches" the circulating influenza virus strains.
On average, vaccine effectiveness ranges from about 50-60%, which means
the vaccine reduces the risk of influenza illness, complications and hospitalization
by that much. Flu viruses constantly change from flu season to flu season
and even during one flu season. While this change (also called "antigenic
drift") may contribute to a decreased match between circulating influenza
virus and the vaccine, the vaccine still provides some protection and
is still the first and best way to protect against influenza.
On average, 5-20% of Americans get influenza each year, resulting in an
estimated 70 million lost work days at a cost of $3-12 billion. Despite
the fact that many healthcare workers care for people with or at high
risk for influenza, flu vaccination coverage among U.S. healthcare workers
was roughly 64% in 2014-2015. To improve patient and healthcare worker
safety and wellbeing, many states and healthcare organizations are adopting
mandatory influenza vaccination policies as a job requirement or condition
of employment. Based on recommendations from the CDC and in keeping with
our mission and conscientious medical care, MDMH has adopted this type
of policy to ensure we are protecting patients, employees and others from
the seasonal flu.
In addition to flu vaccination, other tips to lower your risk of getting
and sharing influenza include calling in sick when you need to; do not
touch your eyes, nose and mouth; practice good respiratory hygiene by
covering coughs and sneezes with the inside of your elbow or tissues;
practicing regular hand hygiene with soap & water or alcohol-based
hand sanitizers; and regularly wiping your desk and other highly contaminated
items with a sanitizing/disinfecting cleaner (e.g., telephone, door handles,
While many people get their flu vaccination as soon as it is available,
it is not too late to vaccinate now.
Please talk to your primary care provider to see if the flu vaccination
is appropriate for you.
For questions and or comments contact Alida Merritt, Katherine Herczeg,
MSN, RN, CPHQ, at Marcus Daly Memorial Hospital's Quality Improvement/Infection
Control Department. Working together to build a healthier community!