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Be aware of spreading influenza strains

by Larry Blumenthal, M.D.
MUSC Student Health Services
After a relatively mild January, widespread influenza activity was reported in 31 states, including South Carolina, during the first week of February. On college campuses across the state, including Clemson University, College of Charleston and the University of South Carolina, a high rate of flu has been reported.
MUSC has undertaken  an aggressive and successful flu vaccination campaign this season to better protect students, faculty, staff and patients. Even with these effort many have experienced acute respiratory illnesses including influenza or other common respiratory viruses that occur in the winter. Almost half of recent influenza cultures appear to be variant  strains of types A influenza H3N2 (Brisbane) and influenza B (Yamagata), which were not included in this year’s vaccine.
Other common respiratory illnesses this time of year include corona-virus, rhinovirus, para-influenza, and respiratory syncytial virus. (See The Catalyst, Oct. 5, 2007)
Influenza viruses are constantly mutating so that immunity (from vaccination or illness) one year will not provide protection from future strains of the flu. Based on the predominant circulating strains of virus in a given year, experts predict which strains of virus to include in the flu vaccine for the following year. Each year’s vaccine contains protection against three influenza strains: two members of the type A family (an H1N1 and an H3N2 strain), and one member from the type B family.
Two strains of flu viruses emerged last February that were too late to be included in this year’s flu vaccine. These strains, the Brisbane/10 and Yamagata influenzas, now account for 44 percent of all flu cultures this winter. It is too early to tell how much protection the current flu vaccine will provide against these variant strains. Even when the flu vaccine is not an ideal match with circulating strains, it can still provide enough protection to prevent or lessen illness severity and prevent flu-related complications.
An annual flu vaccination is essential not only to prevent infection in health care workers, but to prevent spreading the infection to vulnerable patients and family members. The flu vaccine still is available and is free for MUSC employees (through Employee Health) and MUSC students (through Student Health Services).

How does one get the flu?
  • Up to 20 percent of U.S. residents will get the flu each winter. While most people who get influenza will recover in a few days to less than two weeks, some people (the young, the elderly, pregnant women, and those with certain chronic medical conditions) are at high risk for developing life-threatening complications. More than 90 percent of influenza-related deaths occur in persons 60 years of age and older.
  • The influenza virus is typically transmitted from person-to-person by inhaling a respiratory droplet from an infected person’s cough or sneeze.
  • The average incubation period for the influenza virus is one to two days.

What are flu symptoms?
Influenza shares signs and symptoms with many common respiratory infections. What distinguishes the flu from other respiratory viruses is the abrupt onset of symptoms (within hours) as well as the severity of symptoms. These symptoms may include:
  • Fever (usually high)
  • Generalized headache
  • Extreme fatigue
  • Muscle aches
  • Dry cough
  • Sore throat, runny nose, and nasal congestion may be present, though are more commonly associated with the common cold.
  • Duration of symptoms: Fever and muscle aches generally improve within three to five days, though lingering cough and fatigue can last up to a few weeks.
How do I know if I have the flu?
  • Health care providers may diagnose influenza on clinical grounds or may use one of the rapid flu tests that now are available. 
  • Notify your health care provider as soon as possible about your symptoms. Many clinics will provide a mask or have a separate waiting area for patients with flu symptoms. 
  • Antiviral medications (oseltamivir, zanamivir) can decrease the severity and duration of the illness if started within one to two days after onset of symptoms.
  • Hydration: High fever increases the daily fluid requirement by about 10 percent for each degree of fever. If the average adult requires 1.5 - 2 liters of fluid/day from food and drink, this should be increased by about 150 ml of fluid for each degree of fever above normal.
  • Anti-inflammatory medications can reduce the fever and muscle aches associated with the flu. These medications include acetaminophen, ibuprofen, naproxen and aspirin. Aspirin use should be avoided in children and teenagers due to the risk of Reye's Syndrome.
  • Cough medications.
  • Avoid smoking.

How do I keep from spreading the flu?
  • Adults can be contagious to others starting the day before symptoms begin through about five days after illness onset. Viral shedding peaks at 24 to 48 hours of illness and then rapidly declines over the next five days, though longer periods of viral shedding can occur in children and immuno-compromised persons. 
  • The flu virus typically is transmitted by airborne respiratory droplets, so cover your nose and mouth with a tissue when you cough or sneeze, and throw the tissue away after you use it.
  • Wash your hands often with soap and water, especially after you cough or sneeze. If you are not near water, use an alcohol-based hand cleaner.
  • Stay home until symptoms resolve to avoid spreading the flu to patients and colleagues.
How can I prevent getting the flu?
  • Annual flu shots are the most effective way to keep from getting the flu. When the influenza vaccine is well- matched to circulating strains of the virus, it can be expected to reduce laboratory-confirmed influenza by approximately 70 percent to 90 percent in healthy adults 65 years of age and older.  Protective antibodies typically appear two weeks after receiving the flu vaccine.  
  • Antiviral drugs can be used as a second line of defense to treat the flu or to prevent infection when household members or close contacts have been diagnosed with the flu. When taken as prophylaxis, these medications should be started as soon as possible and continued until there is no longer influenza activity in the area. 
For more information, visit;

Friday, Feb. 15, 2008
Catalyst Online is published weekly, updated as needed and improved from time to time by the MUSC Office of Public Relations for the faculty, employees and students of the Medical University of South Carolina. Catalyst Online editor, Kim Draughn, can be reached at 792-4107 or by email, Editorial copy can be submitted to Catalyst Online and to The Catalyst in print by fax, 792-6723, or by email to To place an ad in The Catalyst hardcopy, call Island Publications at 849-1778, ext. 201.