Influenza (a.k.a. "the flu") Virus

Alida Merritt, MSN, RN, CPHQ
Department Head
Quality Improvement/Infection Control
Marcus Daly Memorial Hospital
Hamilton, MT 59840
406-375- 4472

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, computer keyboards).

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!


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