Health Advisory
NEW CASES OF INFLUENZA REPORTED IN DELAWARE

Influenza has been confirmed in Delaware as evidenced by four isolates and a positive rapid test.

Immunization should continue to be offered to unvaccinated persons throughout the influenza season as long as vaccine is still available. Protective antibodies develop in about two weeks. While not a substitute for vaccination, the use of antiviral may be effective in reducing the severity of influenza.

DPH encourages the submission of samples for influenza testing, especially early in the influenza season when information about circulating subtypes is most important. The Delaware Public Health Laboratory (DPHL) offers rapid influenza testing, which will be followed by culture and subtyping, to health care providers in Delaware. Details regarding sample collection and transport can be obtained by calling DPHL at (302) 653-2870. This service is provided free of charge.

Case Information

To date this influenza season the following influenza activity has been reported to DPH.

• Positive rapid test indicating influenza B from a 6 year old Sussex County child on November 11, 2003
• Positive culture indicating influenza A Panama (H3N2) from a Kent County 17 year old on November 18, 2003 (DPH Lab)
• Positive culture indicating influenza A Panama (H3N2) from a Kent County 41 year old on November 20 2003 (DPH Lab)
• Positive culture indicating influenza A from a New Castle County 6 month old child on November 22, 2003
• Positive culture indicating influenza A Panama (H3N2) from a New Castle County 19 year old on November 26, 2003 (DPH Lab)

National Surveillance Trends and
CDC Vaccination Recommendations

Reported by CDC November 21, 2003
CDCHAN-00165-03-11-21-UPD-N

Current surveillance data indicate that the United States is experiencing an early influenza season that could be more severe than in the past 3 years. The situation underscores the need for timely immunization of those people most at risk from serious complications of influenza and the people taking care of them, especially health-care workers.

The United States and some European countries are experiencing influenza morbidity earlier than usual. So far, the majority of the influenza viruses identified in the United States this winter have been type A (H3N2) viruses, which historically have been associated with relatively severe influenza epidemics. Of the influenza A (H3N2) viruses from the United States that have been analyzed at CDC, 78% are similar to the A/Fujian/411/2002 strain, which evolved or "drifted" from the A/Panama/2007/99 strain present in the current vaccine, and the remaining 22% are similar to the vaccine strain. The A/Fujian/411/2002 drift variant was the predominant influenza strain circulating in Australia and New Zealand during their most recent influenza season, which was characterized as "moderately severe." These factors could portend higher morbidity and mortality in the United States during the 2003-04 influenza season.

The influenza vaccine is safe and is the most effective way to prevent the disease and its complications. Although this year's vaccine contains the Panama strain of influenza A (H3N2), it is expected to provide some cross-protection against the Fujian-like viruses that are currently circulating. The other two virus strains (influenza A [H1N1] and influenza B) in the vaccine closely match their circulating counterparts.

CDC recommends the following individuals get vaccinated against influenza:

• Persons 50 years and older;
• Residents of nursing homes and other long-term care facilities that house persons of any age who have long-term illnesses;
• Adults and children 6 months of age and older who have chronic heart or lung conditions, including asthma;
• Adults and children 6 months of age and older who need regular medical care or had to be in a hospital because of metabolic diseases (like diabetes), chronic kidney disease, or weakened immune system (including immune system problems caused by medicine or by infection with HIV);
• Children and teenagers (6 months to 18 years of age) who are on long-term aspirin therapy and therefore could develop Reye syndrome after influenza;
• Women who will be more than 3 months pregnant during the influenza season.

In addition, CDC recommends vaccination of the following groups of people to reduce the risk of spreading influenza to persons at high risk for complications:

• Doctors, nurses, and other employees in hospitals and doctors' offices, including emergency response workers;
• Employees of nursing homes and long-term care facilities who have contact with patients or residents;
• Employees of assisted living and other residences for people in high-risk groups;
• People who provide home care to those in high-risk groups;
• Household members (including children) of people in high-risk groups.

CDC also encourages, when feasible, vaccination of children aged 6-23 months and their caregivers.
The primary contraindication to influenza vaccination is allergy to eggs.

Further Information

• Centers for Disease Control and Prevention Influenza Website :
  http://www.cdc.gov/ncidod/diseases/flu/
• Delaware Public Health Laboratory: (302) 653-2870
• Delaware Immunization Program: 1-800-282-8672