Health Update
INFLUENZA

The Delaware Division of Public Health (DPH) has received two health advisories from the Centers for Disease Control and Prevention which are forwarded as part of this notification.

• FDA and CDC Statement Concerning Rumors About Recalled Lot of Influenza Vaccine
• Clusters of Influenza A Infections Identified (Texas)

The Delaware health care community is reminded that DPH monitors both the occurrence of influenza and adverse reactions to influenza vaccination in Delawareans. Adverse reactions are reported to the national Vaccine Adverse Event Reporting System (VAERS). As of October 21, no evidence of influenza or adverse reactions in Delaware have been identified this year.

Health care providers can call DPH at 1-888-295-5156 to:

• Obtain more information about influenza in Delaware
• Report suspect cases of influenza
• Report adverse reactions
• Obtain procedures for submission of specimens to the DPH laboratory

DPH encourages health care providers to confirm influenza through laboratory evidence and report the findings to DPH. This is especially valuable early in the influenza season so that DPH can advise the health care community of its occurrence in Delaware, the antigenic strain and susceptibility to anti-viral medications.

CDC Advisory 1
FDA and CDC Statement Concerning Rumors
About Recalled Lot of Influenza Vaccine

Rumors have been circulating that a "contaminated" lot of flu vaccine has been recalled by the FDA. This is false. No contamination of any flu vaccine has been identified anywhere in the U.S., and the FDA has not recalled any lot of flu vaccine. Flu vaccine is routinely tested for safety, purity, and potency and all lots released have met these standards. As with any vaccine, flu vaccine is capable of causing some side effects, these are very rarely severe. Most side effects from flu vaccine are mild, such as arm soreness, redness or swelling where the shot was given, fever, or achiness. More serious reactions to the flu vaccine do occur, but they are rare. While FDA and CDC are currently investigating several recent reports of possible significant allergic reactions to flu vaccine, it is important to note that the number and type of reactions reported to date are not unexpected. The reactions reported, not all of which may have been caused by the administration of vaccine, do not, at this time, suggest any problem with the flu vaccine. However, FDA and CDC will continue to investigate these and any other reports and will provide any further information as available. While serious reactions to flu vaccine are rare, each year about 114,000 people in the U.S. are hospitalized and about 36,000 people die because of the flu. The flu vaccine is the best way a person can protect themselves and their loved ones against influenza. October and November are the best months to get vaccinated - however, vaccination in December or later still provides considerable protection.

For more information about influenza, go to http://www.cdc.gov/nip/Flu.

CDC Advisory 2
Clusters of Influenza A Infections Identified;
Reports Underscore Importance of Timely Influenza Vaccination

This Health Alert Network notice describes recent reports of influenza A activity in Texas and other parts of the United States, presents results of preliminary laboratory analysis of influenza A(H3N2) isolates conducted at the Centers for Disease Control and Prevention, and outlines current recommendations for influenza vaccination.

During the first week of October, Texas health authorities reported cases and school outbreaks of laboratory-confirmed influenza A infections in the Houston metropolitan area. Testing in Texas identified influenza A(H3N2) virus and isolates were sent to the Centers for Disease Control and Prevention (CDC) for further characterization. At CDC, preliminary analysis has shown that 8 of 13 A(H3N2) isolates from Texas are antigenically similar to the A(H3N2) A/Panama/2007/99 vaccine strain, while five isolates are antigenic drift* variants. Influenza subsequently has been reported from several counties in Texas.

During August and September, CDC had received influenza A(H3N2) isolates from sporadic cases in Alaska, Connecticut, Wisconsin, Hawaii, New Hampshire, New York, Texas, and the District of Columbia and influenza A isolates from sporadic cases in Louisiana, Texas, and Washington. While influenza activity in the United States usually starts in November or December and reaches peak levels from late December through April, the timing of influenza activity is highly variable from year to year and influenza outbreaks have been reported in October in some previous years. Influenza cases and isolated outbreaks can occur at any time of the year.

Similar to the Texas isolates, approximately 33% of influenza A(H3N2) viruses isolated worldwide between February and September have drifted antigenically from the current A(H3N2) A/Panama/2007/99 vaccine strain in laboratory tests. By contrast, influenza A(H1N1) and influenza B viruses generally have remained similar to their vaccine strain counterparts. Influenza vaccine is expected to provide good protection against influenza A(H1N1), B viruses, and A(H3N2) viruses that are similar to the vaccine strains. While vaccine protection against the A(H3N2) drift variants may be lower, the vaccine is expected to provide some degree of effectiveness although the level of protection cannot be predicted.

Supplies of influenza vaccine are adequate in the United States this year. The adequate supply, coupled with appearance of community influenza activity in Texas in early October, serves as a reminder of the need for timely vaccination against influenza, particularly among persons 6 months of age or older and who are at increased risk for complications of influenza. Such "high-risk" groups include:

• Persons 65 years of age and older
• Women who will be in the second or third trimester of pregnancy during influenza season
• Persons with one of several chronic, long-term health problems (e.g., heart or lung disease, kidney problems, asthma, and HIV/AIDS or any other illness or condition that suppresses the immune system).

Influenza vaccination is also recommended for other target groups, including

• Persons aged 50 to 64 years because of the increased prevalence of high-risk conditions in this age group.
• Health-care workers and others in close contact with high-risk individuals because of the possibility that this group might transmit influenza to persons in high-risk groups.

For the 2003-04 influenza season, influenza vaccination also is encouraged, when feasible, for children 6 to 23 months of age and their household contacts and out-of-home caregivers because young children are at increased risk of influenza-related hospitalization. For 2004-05, influenza vaccination will be recommended for these groups for the first time.

* Antigenic drift is the gradual accumulation of changes in the hemagglutinin (HA) protein of influenza viruses that may affect the binding of antibodies to this virus protein. Since antibodies to the HA are important for protection from influenza, antigenic drift may result in an increase in susceptibility of the population to infection by these antigenically drifted viruses, in spite of previous infection or vaccination.

For additional information about influenza, please see the CDC Website at http://www.cdc.gov/ncidod/diseases/flu/fluvirus.htm.