Dr. Charles John Palenik
Influenza (the flu) is a contagious disease that is caused by influenza viruses. It attacks the respiratory tract in humans (nose, throat and lungs). Incubation is brief — one to three days. Flu usually starts abruptly and may include symptoms such as fever (up to 104o F), headache, sweating, malaise (sometimes extreme), fatigue, dry cough, sore throat, nasal congestion, and myalgia. The "flu season" in the United States runs approximately from November through April each year with a peak in late December through March.
Influenza is spread from person-to-person through mists or sprays produced by coughing and sneezing. Influenza affects all age groups and causes moderate to severe illness. Most people are ill for only a few days.
Influenza can cause epidemics of severe illness and life-threatening complications almost every winter. Epidemics can affect up to 20 percent of the American population and are associated with an average of 36,000 deaths and 114,000 hospitalizations annually. Over 90 percent of deaths occur in persons 65 years or older.
Inactivated (killed) influenza vaccine has been used in the United States for many years. Influenza viruses mutate regularly. Therefore, the influenza vaccine must be updated each year. Protective antibodies take about two weeks to develop after vaccination and may persist for a year. The flu vaccine has an overall protection rate of 70 percent to 80 percent. Efficacy varies by its similarity to the strains of influenza virus presently circulating within the population, age of the recipient, and the presence of underlying illness.
A yearly flu shot is recommended for the following groups considered to be at increased risk for serious complications. These are:
• Persons older than 50 years
• Residents of nursing homes and other long-term care facilities that house persons of any age who have long-term illnesses
• Adults and children more than six months of age who have chronic heart or lung conditions, including asthma
• Adults and children more than six months of age who need regular medical care or had to be in a hospital because of metabolic diseases (e.g., diabetes), chronic kidney disease, or weakened immune system, including those caused by HIV/AIDS or by some type of medication
• Children and teenagers (aged six months to 18 years) who are on long-term aspirin therapy and therefore could develop Reyes Syndrome after the flu
• Women who will be more than three months pregnant during the flu season
A person with the flu can readily give it to others. The following persons should also be vaccinated:
• Healthcare workers in hospitals, clinics, and offices, including those employed in the dental industry
• Employees of nursing homes, assisted living centers and other types of long-term care facilities who have contact with patients or residents
• People who provide home care to those in high-risk groups
• Household members (including children) of people of high-risk groups
The ideal time to receive a flu shot is in October or November. People who should be vaccinated in October include those at highest risk and healthcare workers, including dental personnel. Most adults require a single flu shot each year to prevent influenza. Fortunately, the risk of the vaccine to cause serious harm is extremely small. Problems are usually mild (soreness, redness or swelling at the injection site, fever, or body aches) and these last only a day or two. Discussion with a physician prior to vaccination is required of persons with an allergy to eggs or a previous vaccine or those with a history of Guillain-Barre syndrome.
The Organization for Safety and Asepsis Procedures (OSAP) is the leading source for infection control and human safety and health information in dentistry. A search of the OSAP web site (www.osap.org) will provide 22 links on the topic of influenza.
Dr. Charles John Palenik is an assistant director of Infection Control Research and Services at the Indiana University School of Dentistry. Dr. Palenik has authored numerous articles, book chapters, and monographs, and is the co-author of the popular Infection Control and Management of Hazardous Materials for the Dental Team. He serves on the Executive Board of OSAP, dentistry's resource for infection control and safety.Questions about this article or any infection-control issue may be directed to [email protected].
