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April 14, 2008 (CDC
Week 15)
Since September 30, 2007, 18 counties
have reported 901 positive influenza isolates.
Forty-Four (4.8%) were influenza A (H3N2), 100 (11%) were A,
(H1N1), 436 (48.3%) were A, (Not Typed), and 321 (35.9%)
were influenza B. A majority of the influenza B isolates
looked at further were influenza B, Yamagata (not in this
year’s vaccine). Isolation submission peak the week ending
February 2, 2008 with 12% of all isolates received. The
following 5 weeks each received 9% of all isolates received.
Submissions received have been falling steadily for the past
four weeks with last weeks isolates received accounting for
only 3.8% of all isolates received. Eighteen nursing
home/adult living facilities have reported influenza
outbreaks this season. Ten have been influenza B outbreaks
and 8 have been influenza A. Influenza activity in
Washington State is being reported as Local to the Centers
for Disease Control (CDC). The Mountain and Pacific regions
of the United States reported a majority of isolates this
season as A, H1N1, where as, the rest of the nation reported
a majority of there cases as influenza A, H3N2. The last
part of the season nationwide, influenza B is being reported
more frequently.
Of the 901 isolates, 894 had age and
sex reported. Fifty-one percent were reportedly from
female, and 435 (49%) were from males. (See chart below for
age group percentages).
CDC: Since September 30, 2007,
WHO and NREVSS laboratories have tested a total of 185,938
specimens for influenza viruses and 34,380 (18.5%) were
positive. Among the 34,380 influenza viruses, 25,456 (74.0%)
were influenza A viruses and 8,924 (26%) were influenza B
viruses. Seven thousand seven hundred fifteen (30.3%) of the
25,456 influenza A viruses have been subtyped: 2,110 (27.3%)
were influenza A (H1) viruses and 5,605 (72.7%) were
influenza A (H3) viruses.
During the 2007-08 season, influenza A
(H1), a (H3), and B viruses have co-circulated in the united
States. Influenza A (H3N2) viruses have predominated during
the season overall, however, the most commonly reported
influenza virus has varied by week. From week 40 through
week 3 (September 30, 2007 - January 19, 2008) influenza A
(H1N1) viruses were more frequently reported; from week 4
through week 12 (January 20 – March 22,2008), influenza A
(H3) viruses were more commonly reported; and for weeks 13
through 14 (March 23 – April 5, 2008), more influenza B than
influenza A viruses were reported. The predominant virus has
also varied by region. Influenza A (H3N2) viruses have been
reported more frequently than A (H1N1) viruses in seven of
the nine surveillance regions while influenza A (H1N1)
viruses have predominated circulation this season in two
regions (Mountain and Pacific). The proportion of deaths
attributed to pneumonia and influenza has been above the
epidemic threshold for 13 consecutive weeks. The proportion
of outpatient visits for influenza-like illness (ILI) and
the proportion of outpatient visits for acute respiratory
illness (ARI) were below national baseline levels this
week. ILI decreased in all nine regions compared to week
13, but remained above the region-specific baselines in the
East North Central and West North Central regions. The
proportion of outpatient visits reported for ARI was below
all region and age-specific baselines. Six states reported
widespread influenza activity; 11 states reported regional
influenza activity; 23 states reported local influenza
activity; and 10 states and the District of Columbia
reported sporadic influenza activity. Since September 30,
2007, CDC has received a total of 65 reports of
influenza-associated pediatric deaths that occurred during
the current season.
The composition of the 2008-09
influenza vaccine for the Northern Hemisphere contain
A/Brisbane/59/2007-like (H1N1), A/Brisbane/10/2007-like
(H3N2), and B/Florida/4/2006-like viruses. All three
components have been changed from the 2007-08 Northern
Hemisphere vaccine formulation. This recommendation was
based on surveillance data related to epidemiology and
antigenic characteristics, serological responses to 2007-08
vaccines, and the availability of candidate strains and
reagents.
British Columbia: Influenza activity decreased slightly
in week 13. The number of isolates submitted for testing and
the percent positive for influenza decreased. Influenza B
continued to be reported more often than influenza A in week
13. Reports of outbreaks decreased. The rate of ILI visits
to physicians increased to within the expected range for
this point in the season, but above the historical average.
The rate of ILI visits was the only indicator that increased
in week 13, all others decreased.
March 19, 2008 (CDC
Week 11)
Washington State: Since October 1, 2007, seven hundred
and thirty-one positive influenza isolates from 17 counties
have been reported to Communicable Disease Epidemiology.
Fifty-five percent were A, not sub-typed, 29% were influenza
B, 13% were influenza A, H1N1, and 3% were influenza A,
H3N2. Influenza seemed to peak in week five (February
2 to February 8) with 110 (15% of total for year) positive
isolates. Reported activity has been gradually declining
every since. Pneumonia and influenza deaths have been within
normal ranges for the season. There have been 11 nursing
home outbreaks reported so far this season: 6
influenza B, and 5 influenza A, not sub-typed (see chart 1
below). Reported school absenteeism has been low for
this season with only 40 schools reporting >10% absenteeism
for the whole season. The 20-29 age group had the largest
percent of cases reported (18%), followed by the 10-19 age
group with 14%, and the 5-9 and 30-39 age groups with 13%
each. See Chart 2 below for age groups of reported
cases. There have been two reported pediatrics deaths
this season.
Idaho: Idaho continues
to report widespread influenza activity. The state
laboratory has now sub-typed 77 influenza viral isolates.
Influenza AH1, AH3, and B Yamagata viruses are circulating
across the state. All samples have been forwarded to CDC
for further antigenic characterization and for anti-viral
resistance studies.
British Columbia (BC): Influenza activity
decreased in week 10, although still remains localized in
most health authorities. The rate of influenza-like
(ILI) visits to physicians decreased to below the expected
range for this point in the season. The number of isolates
and proportion of respiratory specimens submitted to BCCDC
that tested positive for influenza decreased. Influenza B
remained the predominant strain reported during week 10,
accounting for 61% of the influenza isolates reported from
the BCCDC laboratory. Reports of laboratory confirmed
outbreaks as well as ILI outbreak reports from schools
decreased. BC Children’s Hospital continues to report
ongoing substantial contribution by RSV.
February 28, 2008 (CDC
Week 8)
Washington State: Thirteen counties have had
at least one laboratory confirmed influenza cases reported
this season. Surveillance cases appeared to peak the week
ending February 2, 2008. Eighteen percent of the cases were
identified as influenza A, H1N1; 2.7% of the cases
were A, H3N2; 309 (59%) percent of the cases were A,
not subtyped; 19% of the cases were influenza B.
A majority of the B cases were B, Yamagata which is not
covered by this year's vaccine. The largest amount of
activity is being reported in the greater Puget Sound area.
Fifty-one percent of cases were reported as female. Illness
seemed to be evenly distributed through the age groups:
8% were less than one year of age, 11% were 0-4 years, 13 %
were 5-9 years, 16% were 10-19 years, 20% were 20-29 years,
13% were 30-39 years, 10% were 40-49 years, 5% were 50-59
years, and 4% were 60 years and over. Three nursing home
outbreaks have reported this year to date. One nursing
home outbreak was influenza A from King County, another was
influenza A from Adams County (onset February 17th, with 39%
of residents ill), and the third was lab confirmed influenza
B, Yamagata from Snohomish County (onset January 31, with
36% of residents ill). Twenty-eight schools have
reported above 10% absenteeism from nine counties this
season. In general absenteeism has been below 20%,
though one school reported 45% absenteeism when a 2A
basketball tournament was held this week. The total number
of schools reporting influenza absenteeism this season is
below average. While influenza is still being reported, the
number of cases being reported from surveillance
laboratories seems to be declining.
British Columbia: Influenza activity appears to
be increasing throughout the province. During week 7,
Fraser, Interior and Vancouver Health Authorities (FHA, IHA,
VIHA) reported widespread activity, while Vancouver Coastal
Health (VCH) and Northern Health Authority (NHA) reported
sporadic activity. The rate of ILI visits to physicians
rose to within the expected range for the first time since
week 2. The number of influenza positive isolates
increased for both reporting labs. Reports of
laboratory confirmed outbreaks in long-term care facilities
(LTCF), as well as ILI outbreaks reports from schools,
remain steady.
WHO Isolates From
Washington State
2007-2008 Season
Reported by WHO/NREVSS Collaborating
Laboratories
February 8, 2008 (CDC
Week 5)
Washington State: Influenza
is widespread with influenza A, H1N1 being the predominate
serotype. Influenza A, H1N1 generally causes less severe
illnesses than influenza A, H3N2. Washington State
surveillance laboratories have reported 7 influenza A, H3N2
isolates this season. Both of the above serotypes are
covered by this years’ vaccine. Influenza B lineages
occurring are B/Yamagata and B/Victoria. Influenza
B/Victoria is covered by this year’s vaccine. Neither of
the influenza B serotypes are occurring in large numbers and
are not causing major concern in Washington or nationwide.
No pediatric deaths have been reported this season, nor have
there been any nursing homes influenza outbreaks reported.
Two schools with influenza-like illnesses reported
absenteeism in November, 2007 and 14 schools have reported
absenteeism above 10% since January 1. Most absenteeism
rates reported are below 15%. This is below the expect rate
of influenza-like absenteeism for this time of the season.
Nine of 29 sentinel physicians have reported influenza
activity at sometime this season. This is below expected
levels for this time of the season. In general, while
influenza activity is widespread, it is at low levels for
most of the state except for the Puget Sound Region.
Oregon and Idaho: Reporting
sporadic to local activity.
British Columbia: Influenza
activity is spreading although it remains lower than
previous years. The rate of influenza-like visits to
physicians remains lower than the expected level. The number
of influenza positive isolates and lab confirmed outbreaks
in long term care facilities as well as school based
outbreaks continue to increase.
January 22, 2008 (CDC
Week 3)
Washington State: Influenza-like illness is being
reported mainly in the Puget Sound region. Sixty
positives influenza isolates have been reported from
sentinel laboratories statewide (Jefferson 2, King 45,
Skagit 3, Snohomish 1, Spokane 2, Whatcom 1, Whitman 4, and
Yakima 2. An additional 60 isolates have been reported
from non-sentinel laboratories mostly in Pierce and
Snohomish Counties. On January 18, four influenza A were
reported from Washington State University students in
Whitman County. So far 33 influenza A, unsubtyped, 19 A,
H1N1, 3 A, H3N2, and 5 B have been laboratory confirmed.
Age groups identified were 0-4 year olds 13, 5-9 year olds
5, 10-19 year olds 8, 20-29 year olds 17, 30-39 year olds 5,
40-49 year olds 5, 50-59 year olds 3, 60-69 year olds 1 and
three with unknown ages. Minimal influenza absenteeism in
schools is being reported. No nursing home outbreaks have
been reported, although King County has reported on going
investigations in several nursing homes. No pediatric
deaths have been reported this season. Influenza-like
activity is being reported as regional to the Center for
Disease Control.
Idaho: Sporadic influenza activity.
Oregon: Sporadic influenza activity
United States: Influenza activity continues to
increase. CDC has antigenically characterized 2,186
influenza isolates; 1,901 (87.0%) were influenza A viruses
and 285 (13%) were influenza B viruses. Five hundred
fifteen (27.1%) of the 1,901 influenza A viruses have been
subtyped: 397 (77.1%) were influenza A (H1), and 118 (22.9%)
were influenza A (H3) viruses.
It is too early in the influenza season to determine
which influenza viruses will predominate or how well the
vaccine and circulating strains will match. The proportion
of outpatient visits for influenza-like illness (ILI) was
above national baseline levels.
The East North Central, Mountain, Pacific, West North
Central and West South Central regions reported ILI above
their region-specific baselines. Four states reported
widespread influenza activity (Colorado, Hawaii, New York,
and Texas); 11 states reported regional influenza activity;
the District of Columbia and 15 States reported local
influenza activity; 19 states reported sporadic influenza
activity; and one state reported no influenza activity.
The proportion of deaths attributed to pneumonia and
influenza was equal to the epidemic threshold. One
influenza-associated pediatric death was reported during
week 1 of the 2007-08 season.
British Columbia: Sporadic activity.
January 7, 2008 (CDC Week 1)
Washington State: Sporadic cases of influenza are
occurring in Washington. To date, 14 cases have been
reported from King County, two each from Skagit and Yakima,
and one each from Snohomish and Spokane Counties. One case
was reported in October, six in November, and thirteen in
December. Sentinel physician reporting of influenza-like
illnesses are within expected levels for this time of the
season, as are pneumonia and influenza deaths. No nursing
home outbreaks have been reported. One school in Yakima
County reported absenteeism with influenza-like (ILI)
illness at 10.9%. A majority of isolates are influenza A,
H1N1.
United States: During weeks 51 and 52, influenza
activity continued to increase in the United States.
Pneumonia and influenza deaths were below the epidemic
threshold.
The proportion of outpatient visits for influenza-like
illness was above national baseline levels. Five states
reported regional influenza activity (AK, AZ, CO, NY and
TX); local activity was reported in 9 states (CA, CT, HI,
IL, MD, MA, MI, MT and VA). Sporadic activity was reported
in the District of Columbia, Puerto Rico and 33 states.
Since September 30, 2007, WHO and NREVSS laboratories
have tested 43,184 for influenza viruses with 2.8 %
positive. Eighty-seven% were influenza A and 12.2% were
influenza B viruses. Of the influenza A, 77% were influenza
A (H1) viruses and 22.4% were influenza A (H3).One pediatric
death has been reported.
British Columbia: During weeks 51 and 52, BC
laboratories reported 46 positive respiratory specimens for
influenza. Laboratory positive influenza has been reported
from all health authorities. Two long-term care facilities
in the Frasier Health District reported influenza-like
illness with one laboratory confirmed as influenza.
Physician visits for ILI illness has been within the
expected range.
December 26, 2007
(CDC Week 51)
Washington
State: A few more influenza A cases have been
reported. No outbreaks related to influenza have
been reported from schools or long term care facilities.
No pediatric deaths have been reported. All indicators
are below or within acceptable perimeters for this time
of year.
United States (CDC week ending December 15,
2007): A low level of influenza activity was
reported in the United States. Nationally, 179 influenza
A, H1N1, 43 A, H3N2, 537 A, not subtyped, and 72
influenza B have been laboratory confirmed this season.
The proportion of deaths attributed to pneumonia and
influenza was below the epidemic threshold. The
proportion of out patients visits for influenza-like
illness and acute respiratory illness was below national
baseline levels. Colorado reported regional influenza
activity; five states (Arizona, Hawaii, Massachusetts,
Texas and Virginia) reported local influenza activity;
36 states, the District of Columbia, and Puerto Rico
reported sporadic influenza activity; and eight states
reported no influenza activity. One pediatric death has
been reported this season.
Idaho, Oregon, British Columbia: Sporadic
influenza is reported in Idaho and Oregon and British
Columbia.
December 18, 2007
(CDC Week 50)
Washington State: Influenza
surveillance laboratories have reported 6 influenza A,
H1N1-like and 1 influenza A, H3N2-like viruses from King,
Snohomish and Yakima. One influenza B has also been reported
from Spokane. Two influenza A that were sent to CDC for
antigenic testing have come back as positive for influenza
A/Solomon Islands/03/2006-like (H1N1) which is an antigenic
variant of A/NewCaledonia/20/99. A/Solomon Islands/03/2006
is the WHO recommended H1 component of the 2007-2008 vaccine
for the Northern Hemisphere and 2008 Southern Hemisphere.
No nursing home outbreaks have been reported. Two schools
have been reported with low absenteeism with respiratory and
gastrointestinal symptoms. No pediatric deaths have been
reported. All other surveillance indicators have been at or
below expected levels for this time of year.
Idaho: The latest report stated low sporadic
influenza activity.
USA: Week Ending December 8, 2007 (CDC Week 49).
During week 49, a low level of influenza activity was
reported in the United States. One hundred twenty-one (4.7%)
specimens tested by U.S. World Health Organization (WHO).
National Respiratory and Enteric Virus Surveillance System (NREVSS)
collaborating laboratories were positive for influenza. The
proportion of deaths attributed to pneumonia and influenza
(P&I) was below the epidemic threshold.
The proportion of outpatient visits for influenza-like
illness (ILI) and acute respiratory illness (ARI) was below
national and region-specific baseline levels. One state
reported regional activity (Texas); six states reported
local influenza activity (Arizona, Colorado, Connecticut,
Florida, Hawaii, W. Virginia); 32 states, the District of
Columbia, and Puerto Rico reported sporadic influenza
activity; and 11 states reported no activity.
Since September 30, 2007, WHO and NREVSS laboratories
have tested a total of 29,488 specimens for influenza
viruses and 709 (2.4%) were positive. Six hundred and 50
(91.8%) were influenza A and 58 (8.2%) were influenza B. Of
the 650 influenza A subtyped, 125 (81.7%) were influenza A
(H1) and 28 (18.3%) were A (H3). CDC characterized 33
influenza viruses (19 influenza A (H1), 11 influenza A (H3),
and three influenza B viruses) since September 30, 2007. All
19 of influenza A (H1) were A/Solomon Islands/3/2006, the
component of the 2007-08 vaccine. A/Solomon Islands/3/2006
is a recent antigenic variant of A/New Caledonia/20/99.
Influenza A (H3) (11): four were characterized as A/Wisconsin/67/2005-like,
the influenza A component of the 2007-08 influenza vaccine.
Seven were characterized as A/Brisbane/10/2007-like a recent
antigenic variant which evolved from
A/Wisconsin/67/2005-like. The Influenza B/
Malaysia/2506/2004-like in this years vaccine is of the
B/Victoria lineage and has not been reported in any
influenza B’s tested this year. All three influenza B
tested have been from the B/Yamagata lineage. It is too
early in the season to determine which influenza viruses
will predominate or how well the vaccine and circulating
strains will match the vaccine. Nationally, one influenza
associated pediatric death has been reported this season.
British Columbia: Sporadic activity.
November 30, 2007
(CDC Week 47)
Washington State: Two
influenza A, H1N1 (King County), and one A, H3N2 (Snohomish
County), have been confirmed at the State Virology
Laboratory since the beginning of October. A few reports
have been reported from various sources of “rapid positive”
influenza tests across the state. Two of these samples
received at the State Virology Laboratory have been negative
for influenza. No other indicator have shown increases in
influenza activity above baseline levels expected at this
time of year.
United States: Nationally, low levels of influenza
activity are being reported. For week 46 (November 11-17),
sixty-four (2.8%) of specimens tested by WHO and NREVSS
collaborating laboratories were positive for influenza,
including 10 influenza A (H1) viruses, one influenza A(H3)
virus, and 53 influenza A that were not subtyped. The
proportion of deaths (pneumonia-influenza), outpatient
visits and acute respiratory illness are below national
baseline levels. No pediatric deaths have been reported for
the current season. Two states reported local
activity; 20 states and the District of Columbia reported
sporadic influenza activity; and 28 states reported no
influenza activity. Florida, Hawaii, and Texas have
accounted for 257 (77.2%) of the 333 influenza viruses
reported this season.
British Columbia: British Columbia is reporting
low sporadic influenza activity.
November 6, 2007
(CDC Week 44)
Washington State: Influenza activity in Washington
State for the month of October was very light. One case of
influenza A, H1N1 was confirmed at the State Virology
Laboratory. No school or nursing home outbreaks were
reported. No pediatric deaths were reported. Sentinel
Physician reports were below median levels, as were
reported pneumonia and influenza deaths.
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