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March 27, 2016

How bad is Influenza or “the flu”?

Depending on the year, the number of deaths from Influenza or “the flu” can range from approximately 3000 in 1986-1987 to as high as 49,000 in 2003 and 2004 in the United States according to the CDC.

To put these number into perspective, about 14,000 people die of AIDS in 2013, and about 33,000 people die yearly in motor vehicle accidents according to the NHTSA.  Influenza is not a problem to be taken lightly.

How is the flu spread?

Influenza viruses are spread via fluid droplets expelled by an infected person coming in contact with the mucus membranes of another person. These droplets are aerosolized during coughing, sneezing, or by talking. Infected individuals are contagious 1 day prior to the presence of symptoms can remain contagious for up to 1 week in previously healthy adults and up to several weeks in immunocompromised individuals.

How do I know if I have the flu or the common cold?

The diagnosing the flu traditionally has been based on the symptoms you have. Symptoms do vary from person to person based on age, overall health and other comorbidities. Some patients will have mild symptoms, and not every patient will have all of these symptoms.

Symptoms include:

Fever, sore throat, myalgia (body aches), headaches, rhinorrhea (runny nose), weakness, fatigue, coughing, watery eyes.

Your healthcare provider may start you on anti viral therapy based solely on your symptoms. Your provider may do a chest x-ray based on your physical exam, or if you are having pulmonary symptoms to exclude pneumonia.

The diagnoses can be tricky because many of these symptoms are the same as many other viruses such as coronavirus (most common cause of “the cold”), rhinovirus (another common cause of “the cold”),  parainfluenza virus, adenovirus, enterovirus, and respiratory syncytial virus. Rapid diagnostic tests available can support the diagnoses, but these tests are only moderately sensitive. The gold standard for testing has been to take viral cultures of the nasal pharyngeal airway.

Why doesn’t my clinician just take a culture for sure diagnosis?

Your clinician might start you on antiviral therapy right away. Even though nasal cultures are very sensitive, they take time to grow and get results. These results can take days. By the time the diagnosis is confirmed, you might be too far out from the first 48-72 hour window for any anti viral medication to be effective in shortening the duration or the magnitude of your illness.

I take the flu vaccine every year, but sometimes I still get sick.

There are thousand of different flu strains every year world wide. Each influenza strain has its own unique set of proteins to make it virulent. These viruses continue to under go genetic drift and shift constantly, leading to new strains. To create a vaccine that will protect against every strain is simply not feasible yet. Even though scientists are working a universal flu vaccine in the future that target very specific non changing elements within the flu virus, that vaccine will not be ready for years to come. Each year, scientists at the CDC do their best to anticipate which strains to include in the next vaccine based on global infection patterns. The mere burden on the pharmaceutical industry to tackle just three major strains is enough to cause shortages in the vaccine supply the United State experienced back in 2004. Secondly, the vaccine takes about 10 to 14 days after administration for your body to build an effective defense against the virus. During this 10-14 day period, if you get exposed to the flu from everyone coughing around you, your body has not loped the immunity it needs to fight of the infection effectively.

  Should I even bother getting the flu vaccine?

The flu vaccine is recommended for everyone especially young children under 5, the elderly, healthcare workers, and people with any comorbidities that will compromise their overall health such as diabetes, cancer, lung disease, renal disease. The exception to this general rule occurred during times severe vaccine shortages where prior was given to the young, elders and immunocompromised.

How else can I prevent spreading the flu?

Preventative measures include limiting contact with sick individuals. As the droplets get aerosolized in a cough or squeeze, the droplets can linger in the air for a few minutes. If you have the flu, cover your nose and mouth with a tissue when you cough, or cough into the crease of your elbow instead of your hand. Promptly dispose of the tissue, and perform frequent handwashing with soap and water or alcohol based hand rubbing agents. Disinfect any surfaces you or the sick individual may touch such as door knobs, handles, countertops, as these are places that droplets may land, or the infected person may touch if they didn’t wash their hands after coughing.

What symptoms need immediate medical care or consultation?

The severity of the flu can range from mild (stuffy nose) to life threatening symptoms. If you lop a rash, it can be a self-resolving viral exanthema or life threatening due to the virus’s destructive effects on platelet activity. Shortness of breath can be the tell-tale sign of an evolving pneumonia or hypoxemia (not enough oxygen in your red blood cells). Neck stiffness, fever and a headache can be signs of viral meningitis. Lethargy and paradoxical irritability (children so ill, that they become more irritable when touched or held instead of calming down) in children are also life threatening signs and symptoms. Other symptoms include confusion, abdominal pain, vomiting, fever that will not abate with acetaminophen or ibuprofen.  If you have any of these symptoms or anything concerns, please see a healthcare provider immediately.

 

References
  1. Estimates of Death Associated with Seasonal Influenza, United States, 1976-2007. Retrieved from http://www.cdc.gov/MMWR/preview/mmwrhtml/mm5933a1.htm?s_cid=mm5933a1_w.
  1. Bourouiba, L. (2013). Violent expiratory events: On coughing and sneezing. J. Fluid Mech. (2014), vol.745, pp. 537-563. Doi:10.1017/jfm.2014.88
  1. Lee V, Yap J, Cook AR, et al. Effectiveness of public health measures in mitigating pandemic influenza spread: a prospective sero-epidemiological cohort study. J Infect Dis. 2010 Nov 1. 202 (9):1319-26.[Medline].
  1. Garcia J. Influenza: high-dose vaccine decreases flu in older adults. Medscape Medical News. August 14, 2014.
  1. Naylor, Nathan. (2016, January 31).  NHTSA Data Confirms Traffic Fatalities Increased In 2012 . Retrieved from http://www.nhtsa.gov/About+NHTSA/Press+Releases/NHTSA+Data+Confirms+Traffic+Fatalities+Increased+In+2012
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