INFLUENZA SURVEILLANCE UPDATE
This is a general update on influenza surveillance activity in Delaware and the nation. Information is also provided for infection
control in the health care setting.
- Reports of influenza-like illness (ILI) and rapid test positive influenza are beginning to increase in Delaware.
- DPH’s classification of the state’s flu status has changed to "widespread," in accordance with the definition
established by the Centers for Disease Control and Prevention. In Delaware, this indicates that there are cases in all three counties.
The state’s status had remained at "regional"(occurring in two counties) during December and early January.
- The Division of Public Health (DPH) has received 45 reports of rapid positive influenza tests this influenza, but actual morbidity is
certainly much greater. Twenty-two (22) of these reports were in January, 2005.
- The DPH Laboratory has tested 116 specimens to date of which 24 had a positive isolate for influenza. Of these, 21 were Influenza A
(H3N2) Wyoming-like virus (related to A/Fujian/411/2002-like), and 3 were Influenza B Shanghai/Jilin-like viruses.
- All hospitals (including outpatients and admissions) in Delaware participate in weekly reporting of ILI to DPH. Reports of ILI
sharply increased during the week of January 2-7, 2005.
- During week 52 (December 26, 2004-January 1, 2005), influenza activity continued to increase mostly in the eastern United States.
- The proportion of patient visits to sentinel providers for ILI is above the national baseline. The proportion of deaths attributed to
pneumonia and influenza is below the national baseline.
- New York, Vermont, and New York City reported widespread influenza activity, 12 states reported regional influenza activity, and 13
states and the District of Columbia reported local activity. Twenty-two states reported sporadic influenza activity and 1 state did not
- Three hundred nineteen (12.1%) specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus
Surveillance System (NREVSS) collaborating laboratories were positive for influenza viruses. Fifty-six isolates were influenza A (H3N2)
viruses, 237 were influenza A viruses that were not subtyped, and 26 were influenza B viruses. Fifty percent of all isolates this season
have been reported from the Mid-Atlantic and New England surveillance regions.
- CDC has antigenically characterized 107 influenza viruses collected by U.S. laboratories since October 1, 2004: eighty-five influenza
A (H3N2) viruses and 22 influenza B viruses. All of the influenza A (H3N2) isolates were characterized as A/Fujian/411/2002-like (H3N2),
which is the influenza A (H3N2) component recommended for the 2004-05 influenza vaccine. Nineteen of the influenza B viruses isolated
this season belong to the B/Yamagata lineage and were characterized as B/Shanghai/361/2002-like, which is the influenza B component
recommended for the 2004-05 influenza vaccine. Three influenza B viruses belong to the B/Victoria lineage and were characterized as
Infection Control in Health Care Settings
In addition to influenza immunization, the following infection control measures are recommended to prevent person-to-person transmission
of influenza and to control influenza outbreaks in health-care facilities:
Respiratory Hygiene/Cough Etiquette
Respiratory Hygiene/Cough Etiquette programs should
be implemented at the first point of contact with a potentially infected person to prevent the transmission of all respiratory tract
infections in health-care settings, including influenza. A Respiratory Hygiene/Cough Etiquette program includes posting visual alerts
instructing patients and persons who accompany them to inform health-care personnel if they have symptoms of respiratory infection;
providing tissues to patients and visitors to cover their mouth and nose when coughing and sneezing; providing dispensers of
alcohol-based hand rubs; ensuring that supplies for handwashing are available where sinks are located; offering masks to persons who are
coughing; encouraging coughing persons to sit at least 3 feet away from others; and having health personnel observe Standard Precautions.
During the care of a patient with suspected or confirmed influenza:
- Wear gloves if hand contact with respiratory secretions or potentially contaminated surfaces is expected.
- Wear a gown if soiling of clothes with patient’s respiratory secretions is expected.
- Change gloves and gowns after each patient encounter and perform hand hygiene.
- Decontaminate hands before and after touching the patient, after touching the patient’s environment, or after touching the
patient’s respiratory secretions, whether or not gloves are worn.
- When hands are visibly soiled or contaminated with respiratory secretions, wash hands with either a non-antimicrobial or an
antimicrobial soap and water.
- If hands are not visibly soiled, use an alcohol-based hand rub for routinely decontaminating hands in clinical situations.
Alternatively, wash hands with an antimicrobial soap and water.
In addition to Standard Precautions, observe Droplet
Precautions during the care of a patient with suspected or confirmed influenza:
- Place patient into a private room. If a private room is not available, place (cohort) suspected influenza patients with other
patients suspected of having influenza; cohort confirmed influenza patients with other patients confirmed to have influenza. Scientific
evidence is insufficient to make a recommendation upon the routine use of negative-pressure rooms for influenza patients.
- Wear a surgical mask upon entering the patient’s room or when working within 3 feet of the patient. Remove the mask when
leaving the patient’s room and dispose of the mask in a waste container.
- If patient movement or transport is necessary, have the patient wear a surgical mask, if possible.
Visitor and Worker Restrictions
- Discourage persons with symptoms of a respiratory infection from visiting patients.
- Exclude health-care personnel with symptoms of respiratory infection from work for the duration of illness.
When influenza outbreaks occur in health-care settings, additional measures should be taken to limit transmission. These include:
- Identify influenza as the causative agent, early in the outbreak, by performing rapid influenza virus testing of patients with recent
onset of symptoms suggestive of influenza. In addition, obtain viral cultures from a subset of patients to determine the infecting virus
type and subtype.
- Implement Droplet Precautions for all patients with suspected or
- Separate suspected or confirmed influenza patients from asymptomatic patients.
- Restrict staff movement between units and buildings.
- For all patients without influenza illness in the involved unit and for whom the antiviralagent is not contraindicated, administer
influenza antiviral prophylaxis according to current
- Administer influenza antiviral therapy to patients acutely ill with influenza, within 48 hours of onset of illness.
- Administer current inactivated influenza vaccine to unvaccinated patients and health-care personnel.
- Offer influenza antiviral prophylaxis to unvaccinated personnel for whom the antiviral agent is not contraindicated and who work in
the affected unit or who are taking care of high-risk patients.
- Consider prophylaxis for all health-care personnel, regardless of their vaccination status, if the outbreak is caused by a variant of
influenza that is not well matched by the vaccine.
- Curtail or eliminate elective medical and surgical admissions and restrict cardiovascular and pulmonary surgery to emergency cases
only, when influenza outbreaks, especially those characterized by high attack rates and severe illness, occur in the community or acute
For Further information:
- Please call DPH, Bureau of Epidemiology at 1-888-295-5156. The number is available during normal business hours and during
non-business hours for emergencies.
- You can obtain additional information about Influenza on the Centers for Disease Control and Prevention website at: http://www.cdc.gov/flu/
Categories of Health Alert messages:
- Health Alert: Conveys the highest level of importance; warrants immediate action or attention.
- Health Advisory: Provides important information for a specific incident or situation; may not require immediate action.
- Health Update: Provides updated information regarding an incident or situation; unlikely to require immediate action.
NOTE: This page is for informational purposes only and dated material (e.g. temporary websites) may not be available.