Health Alert
INFORMATION ABOUT INFLUENZA FOR HEALTHCARE PROVIDERS

The following information is provided by the Delaware Division of Public Health (DPH) regarding the 2010-2011 influenza season.

Surveillance

DPH’s primary method of surveillance is the statewide sentinel physician network. Sentinel physicians are recruited and appointed by DPH and report weekly the percentage of influenza-like illness (ILI) seen during office visits. Sentinel physicians also provide specimens for PCR testing at the DPH Laboratory. ILI is also reported by hospital emergency departments, Federally Qualified Health Centers, the Dover Air Force Base, selected long-term care facilities, selected colleges and universities, the Department of Corrections, and selected day care providers.

An additional component of DPH’s influenza surveillance is based on analysis of specimens submitted to the Division of Public Health Laboratory. This year the Delaware Public Health Laboratory is offering a Real-Time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) method for detection of influenza virus nucleic acids. This service is available to health care providers in Delaware at no charge. For more information, see the Delaware Health Alert issued October 4, 2010 (http://dhss.delaware.gov/dhss/dph/php/alerts/dhan240.html)

DPH activity in Delaware is posted weekly at http://dhss.delaware.gov/dhss/dph/epi/influenzawkly.html

National surveillance data is posted at http://www.cdc.gov/flu/weekly/fluactivity.htm

Infection Control Guidance

Preventing transmission of influenza virus and other infectious agents within healthcare settings requires a multi-faceted approach. The spread of influenza virus can occur among patients, healthcare providers, and visitors. Healthcare providers can also acquire influenza from household or community contacts and, in turn, transmit the virus to patients. The core strategies for preventing the spread of influenza are:

• Administer influenza vaccine to patients and to staff.
• Implement respiratory hygiene and cough etiquette.
• Manage all ill healthcare providers and staff.
• Adhere to infection-control precautions for all patient care activities, especially and aerosol-generating procedures.
• Implement environmental and engineering infection control measures.

More Specific Respiratory Hygiene Recommendations

• When there is increased respiratory infection activity in the community (increased school/work absenteeism, increased office visits for respiratory illness), offer masks to anyone who is coughing.
• When space permits, encourage anyone who is coughing to sit at least three feet away from others in waiting areas.
• Advise healthcare staff to use droplet precautions (wear a surgical or procedure mask for close contact) in addition to standard precautions when examining a patient with symptoms of a respiratory infection, especially if fever is present. These precautions should be maintained for seven days after patient’s illness onset or for 24 hours after the resolution of the fever and respiratory symptoms (whichever is longer) while a patient is in a healthcare facility.
• Healthcare staff should wear respiratory protection equivalent to a fitted N95 respirator during aerosol-generating procedures such as bronchoscopy, sputum induction, intubation and extubation, autopsies, and open suctioning of airways.

Extensive guidance on infection control is available from CDC at:

http://www.cdc.gov/flu/professionals/infectioncontrol/healthcaresettings.htm or

http://www.cdc.gov/flu/professionals/infectioncontrol/index.htm

Rapid Diagnostic Tests

Reliability and interpretation of results

• Reliability depends largely on the prevalence of infection in the population.
• Sensitivities are approximately 50-70% when compared with viral culture or reverse transcription polymerase chain reaction (RT-PCR), and the specificity of rapid diagnostic tests for influenza is approximately 90-95%.
• False-positive results are more likely to occur when disease prevalence in the community is low and are generally found at the beginning and at the end of the flu season.
• False-negative results are more likely to occur when disease prevalence is high in the community.

Minimize false results

• Use rapid diagnostic tests with high sensitivity and specificity.
• Collect specimens as early in the illness as possible (within four to five days of symptom onset).
• Follow manufacturer’s instructions, including proper collection and handling of specimens.
• Consider sending specimens for viral culture or PCR to confirm results of rapid tests, especially when community prevalence of influenza is low and the rapid diagnostic test result is positive, and when the rapid diagnostic test result is negative but disease prevalence is high.

For more information on testing, visit http://cdc.gov/flu/professionals/diagnosis/index.htm

Vaccination

Current guidance can be found at:http://www.cdc.gov/flu/professionals/vaccination/

Antiviral Drug Treatment

Current guidance can be found at: http://www.cdc.gov/flu/antivirals/index.htm

Resources

• DPH influenza website: http://dhss.delaware.gov/dhss/dph/dpc/immunize-flu.html
• DPH Information Immunization Hotline: 1-800-282-8672
• CDC website: http://www.cdc.gov/flu/professionals/index.htm

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