Health Alert
DELAWARE CONFIRMS FIRST INFLUENZA B FOR 2011-2012

Delaware’s Division of Public Health (DPH) reports the state’s first influenza-related hospitalization for the 2011-2012 flu season. On January 5 2012, a 56-year-old woman from Sussex County was admitted to a Delaware hospital with Influenza B. The person was discharged from the hospital on January 8 and is recovering at home. During the first week of 2012, Influenza B accounted for 6 percent of flu cases nationwide while Influenza A accounted for 94 percent. This is the first case of Influenza B in Delaware for the current season. DPH has identified three confirmed cases of Influenza A-H3 during the season.

Reporting

Confirmed cases of influenza and influenza-associated mortality should be immediately reported to DPH, Bureau of Epidemiology at 1-888-295-5156.

Surveillance

Beginning in October each year, DPH monitors the occurrence of influenza and influenza-like illness using 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 Polymerase Chain Reaction (PCR) testing at the DPH Laboratory. ILI is also reported by hospital emergency departments, federally qualified health centers, selected long-term care facilities, selected colleges and universities, the Department of Corrections, and select day care providers. Generally, ILI reports have not increased in Delaware suggesting that influenza, while present, has not yet been widely circulated.

Infection Control Guidance

Preventing transmission of influenza virus within health care settings requires a multi-faceted approach. The spread of influenza virus can occur among patients, health care providers, and visitors. Health care 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 health care 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.

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 health care 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 health care facility.
• Health care 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.

Rapid Diagnostic Tests

Reliability and interpretation of results

• 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 by:

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

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 Bureau of Epidemiology 1-888-295-5156 or 302-744-1033
• DPH website at http://www.flu.delaware.gov
• CDC website: http://www.cdc.gov/flu/professionals/index.htm
• Delaware’s influenza data: http://dhss.delaware.gov/dhss/dph/epi/influenzawkly.html
• National influenza data: http://www.cdc.gov/flu/weekly/fluactivity.htm

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