Seasonal Flu

Prevalence

Each year, between 5% and 20% of the population becomes ill with influenza (cdc, 2009). Between 1990 and 1999, approximately 36,000 influenza associated deaths occurred each year, making it the sixth leading cause of death among adults in the United States (Thompson, et al, 2003). Between 1979 and 2001, more than 200,000 influenza-related hospitalizations occurred each year. Probability estimates show that annual influenza epidemics contribute to 610,660 life-years lost, 3.1 million days of hospitalization, and 31.4 million outpatient visits. High-risk populations such as those over the age of 65, children under 2 years of age, and those with underlying health conditions, show increased rates of serious illness and death from influenza and its complications.

Studies show that adults can shed the infectious influenza virus at least one day before any symptoms appear. They can continue to do so five to ten days after symptoms begin. Additionally, studies show that approximately 50% of influenza infections can be asymptomatic.

Thus, transmitting influenza in the health care setting is a major concern. Health care personnel can easily spread the infection to patients, and many of those patients can be those at the greatest risk for complications including death.

Vaccinations

Influenza vaccines are shown to be 70 – 90% effective in preventing the flu when there is a good match between circulating viruses and those in the vaccine (cdc). In populations where the vaccine might be less effective in preventing influenza, such as the elderly, studies show that those vaccinated experience a 50 – 60% reduction in severity of disease and the incidence of complications, and there is an 80% reduction in deaths (jcaho).

Some believe that getting a vaccination will cause them to get the flu. This is a myth. A flu shot cannot cause the flu, and serious problems from the flu shot are rare. Some side effects from the vaccine can include soreness or redness at the injection site. Those who receive the nasal mist vaccine may experience nasal congestion, runny nose, sore throat, and cough. The risk of a severe allergic reaction is less than 1 in 4 million (cdc). Getting the vaccine is the best protection against the disease.

Approximately 83% of the United States population is specifically recommended for annual vaccination against seasonal influenza; however, less than 40% received the 2008-09 influenza vaccine (cdc). Achieving 60% or higher vaccination levels for health care personnel is a Healthy People 2010 goal. Vaccination rates of 80% or higher might be needed to provide “herd immunity” that can prevent health care associated influenza by immunizing those who care for and live with susceptible people.

In 2005, the American Nurses Association supported a survey of registered nurses regarding influenza vaccines. Findings showed that only 5% of those responding believed that all of their co-workers had received the influenza vaccine the prior year. ANA then launched their campaign “Everyone Deserves a Shot at Fighting Flu” to urge all nurses and health care workers to get their vaccines.

Masks for Seasonal Flu

Transmission of human influenza from person to person is primarily through droplets generated when an individual coughs or sneezes. The droplets are deposited on mucosal surfaces in the upper respiratory tract of those who are nearby, i.e. within 3 feet, of the individual. Transmission can also occur through direct and indirect contact with the infected respiratory secretions.

To decrease the transmission of influenza in the health care environment, a combination of strategies is recommended (www.cdc.gov/flu/professionals/infectioncontrol/maskguidance.htm):

• Place those patients potentially infected/infected with influenza in private rooms
• Have all health care personnel, whether vaccinated or not, wear surgical masks when in close patient contact (i.e. within 3 feet) and don gowns and gloves if contact with respiratory secretions is likely
• Have infectious patients wear surgical masks to help contain respiratory secretions and limit exposure to others
• During periods when community respiratory infections are increased, offer masks to patients showing symptoms of respiratory infection when they present to a health care facility. The patient should wear the mask until either isolated in private room or it is determined that their symptoms are not related to an infectious process requiring respiratory precautions

It is, however, worth noting that no studies have definitively illustrated that use of masks by either health care personnel (whether vaccinated or not) or infectious patients prevents influenza transmission. Requiring non-vaccinated personnel to wear a mask at all times while on duty gives a false sense of security to workers, patients, and visitors.

source: www.cdc.gov/mmwr/preview/mmwrhtml/rr58e0724a1.htm
source: http://www.jointcommission.org/PatientSafety/InfectionControl/flu_monograph.htm
source: Thompson, W.W., et al. Mortality associated with influenza and respiratory syncytial virus in the United States. JAMA 289: 179 – 186, Jan. 8, 2003.