Influenza (Flu)

“Flu” season is almost here and it is time to get prepared for its onslaught.

Influenza is a highly contagious viral infection which is the cause of the “flu.”  It impacts people of all ages.  Though it can occur any time of the year, most cases are reported from October through March, with peaks between December and February of each year.  It affects between 5 to 20% of the U.S. population annually.  It accounts for thousands of lost school and work days.  It can be especially serious in the very young and the elderly.  Each year, more than 200,000 individuals are hospitalized and several thousand people die from the complications of influenza.


Influenza usually presents initially as “cold-like” symptoms with runny nose, nasal congestion, itchy and/ or burning eyes, sore throat, and a dry cough.  Fever (usually 100°F – 102 degrees° F) is usually present and can be associated with chills.  Muscle aches (e.g., body aches) and fatigue are extremely common.  Joint pains, joint stiffness, gastrointestinal manifestations (e.g., diarrhea, nausea, vomiting) may also occur, but are not as common.

The symptoms usually lasts for approximately 7 to 10 days, but the malaise can continue for several weeks. Pneumonia is not an uncommon complication of the influenza virus and can substantially prolong the duration of illness.  Like other viral infections, influenza can also trigger acute flare-ups of asthma and chronic obstructive pulmonary disease (COPD) in susceptible individuals.

The influenza virus spreads from human to human via aerosols created by coughs and/or sneezes of infected individuals.  The incubation period ranges from 18 – 72 hours.  Shedding of the virus continues for 5 – 10 days in most individuals, however the duration of the shedding is longer in young children and immunocompromised persons.


There are rapid diagnostic tests that can directly detect influenza A or B virus-associated antigens or enzymes within 30 minutes by testing material obtained from throat swabs or nasal swabs.  Due to the cost, availability, and sensitivity of these tests, however, most physicians diagnose influenza based on clinical criteria alone.


Most patients with influenza benefit from rest and increased fluid intake and generally recover in a few days, though the fatigue may persist for weeks.  Antiviral medications can reduce the duration and severity of illness.  To be effective, these drugs must be started within 40 hours of the onset of symptoms.  There are two common antiviral medications used in the treatment and prevention of influenza A and B.  The first medication is oseltamivir (i.e., Tamiflu) which is taken orally 75 mg. twice a day for 5 days for individuals over the age of 12.  If using oseltamivir for prophylaxis for individuals 5 years of age and over, the dose is 10 mg. once a day for 10 days, but can be used in adults and adolescents (13 years of age and older) for up to 6 weeks for a community outbreak.  Smaller doses are given to children between the ages of 1 and 12.  The second medication is called zanamivir (Relenza) and is taken by inhalation using a Diskhaler (i.e., a device similar to an asthma inhaler) 10 mg. twice a day for 5 days for individuals 7 years of age and over.  If using zanamivir for prophylaxis for individuals 5 years of age and over, the dose is 10 mg. once a day for 10 days, but can be used in adults and adolescents for up to 28 days for a community outbreak.  Zanamivir should not be used by anyone who has respiratory problems such as asthma or other lung diseases.


Avoiding exposure to infected individuals and maximizing personal hygiene (e.g., frequent hand-washing with soap and water, not touching one’s nose and eyes) are the first line of defense in preventing the spread of the influenza virus.

Each year in U.S., vaccines that contain antigens from the strains most likely to cause infection during the winter flu season are produced.  These vaccines become effective 10 – 14 days after administration. It is recommended that all persons 6 months of age and above receive a routine annual influenza vaccination.

Only injectable vaccines are recommended for use during the 2017 – 2018 season.  The live nasal spray vaccine (e.g., FluMist) is not recommended due to concerns about its effectiveness against the H1N1 strains of the viruses.  A number of inactivated as well as recombinant vaccines are available for this season. Trivalent vaccines are designed to protect against three different influenza viruses (2 influenza A viruses and 1 influenza B virus). Quadrivalent vaccines protect against the same three viruses as the trivalent vaccine plus an additional influenza B virus.

In 2016, only about 50% if children ages 6 months to 17 years of age received the vaccine.  In adults 65 years of age and above, approximately 66% received the vaccine.  In individuals from ages 18 through 64, the percentage of people vaccinated for influenza was less than the two cohorts mentioned above.  Needless to say, there is great room for improvement in vaccinating the population against such a potentially virulent illness.

Special Populations:

Pregnant women can receive any licensed inactivated or recombinant trivalent or quadrivalent vaccine.  It is always advisable to check with your Obstetrician/Gynecologist physician and get his or her approval before receiving a flu vaccination.

Children between 6 months and 8 years of age who have never been vaccinated will require two doses of influenza vaccine administered at least 4 weeks apart.  If a child received two or more doses before July 1, 2017, only one dose of 2017 – 2018 flu vaccine is recommended.

As per the Centers of Disease Control and Prevention (CDC), children and adults with a history of severe allergic reaction to egg (i.e., any symptom other than hives) should receive the influenza vaccine in a medical setting under the supervision of a healthcare provider who is able to recognize and manage severe allergic conditions.  A previous severe allergic reaction to the flu vaccine, regardless of the component suspected of being responsible for the reaction, is a contraindication to future receipt of the vaccine.

The board certified allergy doctors at Black and Kletz Allergy have 3 convenient office locations in the Washington, DC, Northern Virginia, and Maryland metropolitan area.  Our offices are located in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA.  We diagnose and treat both adult and pediatric patients.  The allergists at Black & Kletz Allergy are extremely knowledgeable about vaccinations as we specialize in immunological conditions. In addition, we also specialize in allergies (environmental, foods, insect stings, medications), asthma, sinus problems, eczemageneralized itching (pruritus)hives (urticaria)swelling episodes (angioedema), and eosinophilic disorders (e.g., eosinophilic esophagitis).  Each one of our offices offers on-site parking and the Washington, DC and McLean, VA offices are Metro accessible.  There is a free shuttle service that runs between our McLean, VA office and the Spring Hill metro station on the silver line.

If you would like to make an appointment to see one of our board certified allergists, please call us today.  Alternatively, you may click Request an Appointment and we will respond to your inquiry within 24 hours by the next business day.  Black & Kletz Allergy has been serving the Washington, DC and Northern Virginia metro area for more than 50 years and we look forward to helping you with you allergy, asthma, and immunologic needs.