-
Educate providers to report aggregate totals
of influenza-like illness weekly to the local health department.
Transmit this information weekly to the West Virginia Infectious
Disease Epidemiology Program (IDEP).
-
Educate laboratories to report aggregate
totals of culture-confirmed influenza, by type and subtype (if
available) to the local health department on a weekly basis. Transmit
this information weekly to IDEP.
-
Recruit one sentinel provider or laboratory
per county for influenza season; no later than November 1, annually.
Report this information to the West Virginia Department of Health and
Human Resources influenza surveillance coordinator to complete the
enrollment process. Successful provider recruitment and retention
requires:
-
Think broadly about provider recruitment.
Clinics, physician assistants, nurse practitioners, university
health centers, family practice residency programs, and many others
make good sentinel providers.
-
Make a personal recruiting visit.
(Suggestion: ask your regional epidemiologist to help).
-
Explain influenza surveillance using a
recruitment package, including:
-
A letter from the local health
department;
-
Information on the CDC influenza
surveillance system;
-
WVDHHR information sheets;
-
Enrollment form; and
-
Virology collection instructions.
-
Identify and communicate with a point of
contact (POC) in the sentinel provider office.
-
Send the completed enrollment form to DHHR.
You will receive the virology collection kit by return mail.
-
Deliver the kit to the POC.
-
Keep the lines of communication open.
-
For the 2003-2004 influenza season (optional
for counties participating in the pilot test for syndromic
surveillance) collaborate with IDEP to capture the following
information on a weekly basis from participating emergency rooms:
-
Emergency room visits with a diagnosis of
influenza or pneumonia.
-
Total number of emergency room visits per
week.
Procedure: Record total ER visits from
Friday through Thursday on Friday morning. Record total ER visits
with a diagnosis of influenza or pneumonia (ICD -10 = J10 - J18).
Submit to IDEP on the Friday of each week with the ILI and
chickenpox totals for the week.
-
Educate providers and the public about
appropriate use of influenza vaccine to prevent influenza.
-
If vaccine-strain influenza is identified
in the county or the state, issue an alert to providers in your
county. Inform them about:
-
The type and subtype of influenza virus
identified in the county or state, and
-
Preventive measures for unimmunized
high-risk patients.
-
If non-vaccine strain influenza is
isolated, contact IDEP immediately. Consult with IDEP for
recommendations specific to the situation. If the situation is of
concern (unexpected and/or virulent strain), you may be asked to:
-
Initiate active surveillance for
clusters/outbreaks of influenza-like-illness through emergency
rooms, schools and nursing homes;
-
Work with local providers to obtain
additional cultures from patients who meet the case definition of
influenza-like illness. The purpose of this is to confirm limited
versus widespread circulation of non-vaccine-strain virus; and
-
Issue an alert to providers in your
county notifying them of the situation.
-
Rapidly triage reported outbreaks of
"influenza-like illness" by obtaining the following
information:
-
Number of ill persons
-
Setting (school, nursing home,
community, etc.)
-
Age distribution of ill persons
-
Do ill individuals have underlying
disease or are they previously healthy?
-
Symptoms
-
Date(s) of onset of illness
-
Duration of illness – time to full
recovery
-
Any results of rapid testing or culture
for influenza?
-
Does anyone have pneumonia? How many?
-
Results of sputum gram stain and blood
cultures, and other studies, if applicable
-
Are any patients sick enough to be in
the hospital? How many?
-
Are any patients moribund? How many?
-
Has anyone died? How many?
-
Name and phone number of person
reporting illness
-
Notify IDEP immediately when an outbreak
of influenza-like illness is reported. Remember that many other
agents (including bioterrorism agents) can mimic influenza in the
early stages. If there is reason to consider bioterrorism (sudden
onset of illness in large numbers of people, unusual severity or
rapid progression in previously healthy individuals, atypical
epidemiological or clinical features, etc.), contact IDEP
immediately. Especially in high-risk populations, anticipate that
you may be asked to investigate influenza outbreaks as follows:
-
Work with providers to obtain
approximately eight to 10 culture samples for viral isolation at
the West Virginia Office of Laboratory Services prior to
initiation of antiviral agents.
-
Obtain a description of symptoms among a
sample of eight to 10 ill persons.
-
For nursing home outbreaks, advise
providers to initiate antiviral prophylaxis according to current
recommendations (MMWR, April 25, 2003 / 52(RR08).
-
If a community outbreak is confirmed as
influenza A through rapid testing, issue a medical alert to
providers with recommendations as in item 6 above.
-
Modify recommendations as necessary, as
additional laboratory data becomes available.
To reduce hospitalization and
mortality from influenza by encouraging widespread use of the influenza
vaccine among high-risk groups.
-
After influenza is identified in the
community, reduce further hospitalization and death from influenza by
educating providers to:
-
Offer the influenza vaccine immediately to
high-risk persons who have not yet received the vaccine AND cover
those individuals with an appropriate antiviral agent until two
weeks after immunization is complete; OR
-
Providers may also cover selected
high-risk individuals who cannot receive influenza vaccine with an
appropriate antiviral agent for the duration of influenza season or
during peak influenza season.
-
If an influenza outbreak is identified in a
long term care facility, advise providers to reduce the risk of
illness by assuring that antiviral prophylaxis is offered to residents
and staff and appropriate isolation measures are instituted.
-
To identify the earliest case of influenza A
in the state (county) and report/feedback data in real time.
-
To estimate the duration of influenza season
from start to finish and report/feedback data in real time.
-
To identify institutional and
community-based outbreaks of influenza and report/feedback information
on circulating strains in real time.
-
To determine if early season, outbreak, and
late season strains are vaccine-strain or non-vaccine-strain and
report/feedback information in real time.
-
To contribute to the global (WHO) effort to
identify appropriate strains of influenza vaccine to formulate vaccine
composition recommendations for the coming year.
Epidemics of influenza occur
every winter and are responsible for an estimated 36,000 deaths per year
in the United States. Most vulnerable to hospitalization or death from
influenza are the very young, the very old, and persons with chronic
conditions. In elderly populations, influenza vaccine is NOT highly
effective in preventing influenza-like illness; it IS effective in
preventing hospitalization and death.
The nation continues to be on alert for another
wave of terrorism in the wake of the September 11 terrorist attacks. Some
researchers believe that a mutated flu virus could be used as a weapon for
a bioterrorist attack. In addition, many bioterrorism agents may exhibit
"flu-like" symptoms in the prodrome phase. Thus it is imperative
to recognize that public health must closely track influenza-like illness
in the community.
Influenza A and B are the two "types"
of influenza that are capable of causing epidemic disease. Influenza A is
further categorized into "subtypes" based on the two surface
antigens: hemagglutinin (H) and neuraminidase (N). Due to "antigenic
drift" (small mutations in the genes coding for the antigenic
structure of the virus), the virus is continually able to evade the human
immune response, and the composition of the vaccine must change every year
to match circulating influenza virus strains and provide optimal
protection. Antigenic shift is a far more drastic change in antigenic
structure, and represents emergence of a completely new subtype, which is
likely to result in pandemic influenza with large numbers of deaths.
Thus, virologic surveillance is a very important
part of influenza surveillance, and is routinely used by the public health
community to answer the following questions:
-
Are early season isolates vaccine
strain? This is an important question to answer because it is the
earliest indicator that the circulating strains are covered in the
current vaccine.
-
Are outbreak isolates vaccine strain?
Again, it is important to know if outbreak strains are covered by the
vaccine because immunization is a critical part of outbreak control.
In addition, outbreak strains are used to formulate recommendations
for the composition of influenza vaccine during the coming year.
-
Are late season isolates similar in
antigenic structure to last year? Late season isolates are considered
in the design of the next season’s influenza vaccine.
-
Are reports of influenza-like illness due to
influenza? In West Virginia, influenza-like illness is reportable, and
the data usually show a seasonal upsurge in the number of cases every
year sometime between December and March. Laboratory confirmation of
this phenomenon adds to the credibility of the ILI data.
In West Virginia, virologic surveillance is
conducted through the sentinel physician system and through sentinel
laboratories. These laboratories submit specimens to the West Virginia
Office of Laboratory Services, which confirms isolation and subtypes
isolates of influenza A.
Rapid turnaround of influenza data is important
so that providers know when influenza season begins and when it is over.
Certain high-risk patients may be offered prophylaxis for the duration of
influenza season.
Pandemic influenza occurs due to antigenic
shift. The first recorded influenza pandemic is thought to have occurred
in 1580. Since then, 31 pandemics have been described, the worst having
occurred in 1918-1919 when 21 million people died worldwide, with 549,000
of these in the U.S. Another pandemic is thought to be inevitable, though
no one knows when it will occur. Good quality influenza response during a
routine year is good practice and necessary for pandemic readiness.
Influenza is an acute illness
characterized by fever, chills, sweats, headache, arthralgia, myalgia,
prostration, coryza, sore throat, and cough. Symptoms are generally
self-limited within two to seven days, though cough may be prolonged.
Elderly patients are at highest risk for
influenza-related complications. These include viral or bacterial
pneumonia, exacerbation of chronic lung disease, myositis, Guillan-Barre
syndrome, and Reye syndrome. Patients with cardiac disease are at
significantly increased risk of death from influenza. Young children age
0-1 years are hospitalized at rates comparable to elderly (age >
65) persons.
There are three types of
influenza viruses: types A, B, and C. Influenza A includes three subtypes
(H1N1, H3N2, and H2N3) that have caused pandemic disease. Influenza B has
caused local and regional outbreaks. Influenza C is a cause of smaller
outbreaks and sporadic cases.
Influenza viruses are classified as follows:
Type/Geographic Site of Isolation/Culture
Number/Year of Isolation(Subtype)
The following are classification examples:
A/Beijing/262/95(H1N1)
A/Sydney/5/97(H3N2)
B/Yamanashi/166/98
Humans. Birds and swine are
thought to be a source of new human subtypes that arise through genetic
reassortment. These new subtypes may then be responsible for pandemic
disease.
Airborne spread predominates
in closed places. Transmission may also occur through direct contact as
the virus survives for hours in the cold and at low humidity.
The incubation period is one
to three days.
The infectious period is
probably three to five days after clinical onset in adults, and up to
seven days after onset in young children.
Outbreaks are commonly
recognized based on clinical and epidemiological features. Laboratory
confirmation/investigation of outbreaks is important in high-risk settings
such as nursing homes or hospitals, or early or late in influenza season,
or anytime that unusual clinical or epidemiological features are noted.
With the availability of antiviral agents, outbreak recognition and
control are increasingly important. Health departments should have the
most recent MMWR recommendations readily available to share with providers
during influenza season.
For surveillance purposes,
ILI is defined as fever $
100E F (36E
C) and cough or sore throat without another identified cause.
The Office of Laboratory
Services offers rapid culture confirmation for influenza A and B on
nasopharyngeal swab samples. Results are shared by fax or phone. Testing
is limited to physicians and laboratories participating in sentinel
surveillance, and health departments engaged in outbreak investigation.
Consult the Infectious Disease Epidemiology Program at (304) 558-5358 if
testing is needed in special situations.
The inactivated influenza
vaccine is the only vaccine currently licensed for prevention of
influenza, and must be given annually during October through November. The
vaccine is recommended for:
-
Persons at increased risk for complications,
including:
-
Persons aged > 65 years;
-
Residents of nursing homes and other
chronic care facilities that house persons of any age who have
chronic medical conditions;
-
Adults and children who have chronic
disorders of the pulmonary or cardiovascular systems, including
asthma;
-
Adults and children who have required
regular medical follow-up or hospitalization during the preceding
year because of chronic metabolic diseases (including diabetes
mellitus), renal dysfunction, hemoglobinopathies, or
immunosuppression (including immunosuppression caused by medications
or by human immunodeficiency [HIV] virus);
-
Children and teenagers (aged six months to
18 years) who are receiving long-term aspirin therapy and therefore
might be at risk for developing Reye syndrome after influenza
infection; and
-
Women who will be in the second or third
trimester of pregnancy during the influenza season.
-
Persons aged 50-64 (because of the higher
prevalence of chronic conditions in this age group).
-
Persons who can transmit influenza to those
at high risk, including:
-
Physicians, nurses, and other personnel in
both hospital and outpatient-care settings, including emergency
response workers;
Employees of nursing homes and chronic-care
facilities who have contact with patients or residents;
Employees of assisted living and other
residences for persons in groups at high risk;
Persons who provide home care to persons in
groups at high risk;
Household members (including children) of
persons in groups at high risk; and
Household contacts and out-of-home
caretakers of children 0-23 months of age.
-
Influenza vaccine is encouraged for the
following groups, depending upon vaccine
availability:
-
All children six to 23 months of age.
-
Persons who provide essential community
services.
-
Students and other persons in
institutional settings (e.g. those who reside in dormitories).
-
Certain travelers (e.g. travel to the
tropics; travel with organized tourist groups at any time of year;
or travel to the Southern Hemisphere during April-September).
-
Anyone who wishes to reduce the likelihood
of becoming ill with influenza.
The live attenuated influenza vaccine (LAIV)
is licensed for healthy children and adults aged 5-49 (MMWR September
26, 2003 / Vol. 52 / No. RR-13 ).
Contraindications to the use of the LAIV include:
-
Persons aged < 5 years and those aged >
50 years
-
Persons with asthma, reactive airways
disease or other chronic disorders of the pulmonary or cardiovascular
systems; persons with other underlying medical conditions, including
such metabolic diseases as diabetes, renal dysfunction, and
hemoglobinopathies; or persons with known or suspected
immunodeficiency diseases or who are receiving immunosuppressive
therapies;
-
Children or adolescents receiving aspirin or
other salicylates (because of the association of Rye syndrome with
wild-type influenza infection);
-
Persons with a history of Guillain-Barré
syndrome;
-
Pregnant women;
-
Persons with a history of hypersensitivity
in clinical anaphylaxis, to any of the components of LAIV or to eggs;
or
-
Persons who are close contacts of persons at
risk for complications from influenza.
In addition to influenza vaccine, there are now
three antiviral agents licensed to prevent influenza. Amantadine and
rimantidine are licensed in individuals > 1 year of age for
prevention of influenza A. Oseltamivir is licensed in individuals age 13
and older for prevention of influenza A and B. These agents can be used
for prophylaxis of high-risk individuals who receive the vaccine after the
start of influenza season. Prophylaxis must be continued for two weeks
after completion of immunization (two weeks after immunization in adults
and for up to six weeks in children receiving the two-dose regimen, i.e.
four weeks after the first dose followed by two weeks after the second
dose). These agents can also be used alone for prophylaxis of those few
high-risk individuals who cannot receive influenza vaccine. Package
inserts should be consulted for additional information.
-
Proportion of MMWR weeks for which reporting
of total ILI is available (county level).
-
Proportion of counties in which virologic
surveillance was conducted during the season (state level).
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