Influenza ("Flu")

Dr. Terry Murphy

ED Medical Director

Samaritan Hospital

Every year in the United States, 15 to 60 million people get the flu; that's 5 - 20% of the population.  And if all those people suffering from fever, chills, aches, cough and fatigue weren't bad enough; consider the economic consequences of lost time from work, reduced productivity at work, doctors/clinic visits and medication expenses (hundreds of millions of dollars per year).  Even worse, more than 200,000 people require hospitalization and intensive treatment for complications of the flu - pneumonia, dehydration, blood stream infections.  And, on average, 36,000 people die each year.  People at the extremes of age; those with chronic medical illnesses such as diabetes, COPD or congestive heart failure; and patients who are being treated for cancer or otherwise on medications that suppress their immune systems are at greatest risk of serious complications or death.  And those are average numbers - some years are worse than others.

So the value of preventing widespread outbreaks of the flu in terms of physical misery, death and the effects on the economy are tremendous.

The "flu" is a contagious respiratory infection caused by specific viruses called influenza virus. Infection with influenza virus causes symptoms that are much more profound than simple "cold" virus.  Generally people have high fever (101 degrees or higher), headache, muscle aches and fatigue; as well as runny nose, cough and sore throat.  Typically symptoms onset within 3 or 4 days of exposure and usually persist for 7-10 days.  The flu viruses are spread in respiratory droplets that can be transmitted up to three feet through coughing and sneezing.  The droplets of viruses can also be transmitted by hand contact with an infected person who has not washed their hands; by picking up viruses from surfaces of countertops, sinks, towels or other objects; and by direct mucous membrane contact, such as kissing an infected person.  Unfortunately people are able to pass on the virus before they have symptoms, as well as for a week after they feel ill.

Early in the illness, because both are contagious respiratory illnesses caused by viruses; it may be difficult to determine whether someone has a cold or the flu because the illnesses share many symptoms.  Generally, as the disease progresses, people with the flu have higher fever, worse headache, muscle aches and fatigue than people with a cold.   Treatment for both illnesses is symptomatic (antibiotics are of no value against them); that is, acetaminophen or ibuprofen for fever or muscle aches, cough medicine for coughing, etc.  Both illnesses improve with rest and fluids.

It is important to attempt to make a distinction between a cold and the flu in patients at high risk for complications of the flu; because the flu is associated with many more medical complications such as pneumonia, dehydration, blood infections, etc. Also for unvaccinated patients, there is some reduction in length and symptoms with early treatment with antiviral medication.  Four antiviral medications (amantadine, rimantadine, oseltamivir, and zanamivir) provide some lessening of the symptoms and shortening of the course of viral influenza if the infection is diagnosed early and treatment is begun (within the first 48 hours of symptoms); however, they are not a substitute for immunization. .  Often a nasal swab will be needed to determine whether influenza viruses are present

Vaccination is 70% effective in preventing influenza, and the flu vaccination is available either by injection or nasal mist.  The injectable form of vaccine, the "flu shot" uses the killed viruses; whereas the nasal mist uses a "weakened' form of live viruses.  Since it takes about 2 weeks after immunization to develop antibodies to the viruses, and because the antibodies produced are usually effective for 4 - 6 months; the timing of administration of the vaccine is important.  The administration should be late enough in the year that it provides antibody coverage through March; but not so late that antibodies are not produced for an "early" flu outbreak in October or November.  The CDC recommends immunization campaigns begin in late October and November.

The "flu shot" is recommended for:

All children 6 months to 5 years

Adults who are 50 or older

Children and adults age 5 - 50 who have chronic medical conditions

Women who will be pregnant during flu season

All residents of long term care facilities

All health care workers

Care givers and household contacts of high risk groups

People should not be vaccinated if:

They have an allergy to chicken eggs

They have had a severe reaction to the influenza vaccine previously

They have had Guillain -Barre syndrome within 6 weeks of getting the influenza vaccine previously

They are sick with a fever

Unlike the "flu shot", the nasal mist vaccine is made of live, but weakened, viruses; therefore, it is recommended only for healthy people 5 to 50 years of age who are not pregnant.

This article is intended to provide useful information, not medical advice. This information cannot, and is not meant to, replace consultation with your physician regarding your individual circumstances.