FluView 2010-2011: Weeks 40-39

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-2

Re: FluView 2010-2011: Weeks 40-2

During week 2 (January 9-25, 2011), influenza activity in the United States decreased in several indicators, but it is unlikely that influenza activity for this season has peaked.

* Of the 4,983 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 1,288 (25.9%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold.
* Two influenza-associated pediatric deaths were reported. One of these deaths was associated with an influenza A (H3) virus and one was associated with an influenza A virus for which the subtype was not determined. The death reported in week 1 from New York occurred in a Georgia resident; therefore the case counts have been updated to indicate this change in classification from New York to Georgia.
* The proportion of outpatient visits for influenza-like illness (ILI) was 2.9%, which is above the national baseline of 2.5%. Three of the 10 regions (Regions 2, 4, and 5) reported ILI above region-specific baseline levels. Four states experienced high ILI activity, New York City and nine states experienced moderate ILI activity, seven states experienced low ILI activity, 30 states experienced minimal ILI activity, and data were insufficient from the District of Columbia.
* The geographic spread of influenza in 17 states was reported as widespread; 15 states reported regional influenza activity; the District of Columbia and 12 states reported local influenza activity, and Guam, Puerto Rico, the U.S. Virgin Islands, and six states reported sporadic influenza activity.

Eight (8%) of the 122 viruses were identified as belonging to the B/Yamagata lineage of viruses.
http://www.cdc.gov/flu/weekly/

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-3

Re: FluView 2010-2011: Weeks 40-3

During week 3 (January 16-22, 2011), influenza activity in the United States increased.

* Of the 5,823 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 1,754 (30.1%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold.
* Three influenza-associated pediatric deaths were reported. Two of these deaths were associated with influenza A (H3) virus infection and one was associated with an influenza B virus.
* The proportion of outpatient visits for influenza-like illness (ILI) was 3.6%, which is above the national baseline of 2.5%. Six of the 10 regions (Regions 2, 3, 4, 5, 6, and 7) reported ILI above region-specific baseline levels. Nine states experienced high ILI activity, eight states experienced moderate ILI activity, New York City and nine states experienced low ILI activity, 24 states experienced minimal ILI activity, and data were insufficient from the District of Columbia.
* The geographic spread of influenza in 25 states was reported as widespread; 16 states reported regional influenza activity; the District of Columbia and four states reported local influenza activity, Puerto Rico, the U.S. Virgin Islands, and four states reported sporadic influenza activity, Guam reported no influenza activity, and one state did not report.

One (0.8%) of these 123 viruses showed somewhat reduced titers with antisera produced against B/Brisbane/60/2008

Lab-confirmed hospitalization rate per 100,000 as reported by:
FluSurv: ages 0-4: 12.1 / ages 65+: 12.2 (NOTE: 45.8% of pediatric hospitalizations and 17.4% adults had no known medical conditions)
EIP: ages 0-4: 9.9 / ages 65+: 11
http://www.cdc.gov/flu/weekly/

 

[JimO]

Re: FluView 2010-2011: Weeks 40-4

Re: FluView 2010-2011: Weeks 40-4

http://www.cdc.gov/flu/weekly/index.htm#OISmap

During week 4 (January 23-29, 2011), influenza activity in the United States increased.

• Of the 6,209 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 2,044 (32.9%) were positive for influenza.
• One human infection with a novel influenza A virus was reportedd.
• The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold.
• Six influenza-associated pediatric deaths were reported. Four of these deaths were associated with influenza B viruses, one of these deaths was associated with an influenza A (H3) virus, and one was associated with a 2009 influenza A (H1N1) virus.
• The proportion of outpatient visits for influenza-like illness (ILI) was 4.0%, which is above the national baseline of 2.5%. Seven of the 10 regions (Regions 1, 2, 3, 4, 5, 6, and 7) reported ILI at or above region-specific baseline levels. Seventeen states experienced high ILI activity; three states experienced moderate ILI activity; New York City and 10 states experienced low ILI activity; the District of Columbia and 19 states experienced minimal ILI activity, and one state had insufficient data.
• The geographic spread of influenza in 30 states was reported as widespread; 15 states reported regional influenza activity; the District of Columbia and one state reported local influenza activity; Puerto Rico, the U.S. Virgin Islands, and four states reported sporadic influenza activity, and Guam reported no influenza activity.

 

[JimO]

Re: FluView 2010-2011: Weeks 40-4

Re: FluView 2010-2011: Weeks 40-4

http://www.cdc.gov/flu/weekly/index.htm#OISmap

The past three weeks look very similar to the beginning of the fall 2009 outbreak.

 

[JimO]

Re: FluView 2010-2011: Weeks 40-4

Re: FluView 2010-2011: Weeks 40-4

http://www.cdc.gov/flu/weekly/index.htm

Antigenic Characterization:
CDC has antigenically characterized 416 influenza viruses [46 2009 influenza A (H1N1) viruses, 188 influenza A (H3N2) viruses, and 182 influenza B viruses] collected by U.S. laboratories since October 1, 2010.

2009 Influenza A (H1N1) [46]

•All 46 were characterized as A/California/7/2009-like, the influenza A (H1N1) component of the 2010-11 influenza vaccine for the Northern Hemisphere.​

I believe that it is notable that all the reported pH1N1 samples tested were similar to A/California/7/2009 even though the CDC released sequences from December and January that are nearly identical to the mutated pH1N1 strain that predominated in the UK recently. Either the data in this week's report lags current sequences by 6 to 8 weeks or the genetic changes in the virus are not recognized by the CDC as being different from A/California/7/2009.

If the data are accurate and lagging recent infections, then that suggests that there could be two different pH1N1 viruses co-circulating and would explain why pH1N1 has been reported in some states since early December, but only in the past three weeks (after the UK epidemic had occurred) has there been a significant increase in infections and more serious cases developing.

 

[jeff]

Re: FluView 2010-2011: Weeks 40-4

Re: FluView 2010-2011: Weeks 40-4

Looking at the fluview charts, does seem that the highest hospitalization rates are in the either young and over 65 years. Am I looking at it wrong. Which would be the normal pattern for a flu season. The thing that always is confusing is the CDC says the flu is increasing but by the graph it looks like it is decreasing and then we have the P&I spike????? Very confused
Thanks for posting.

 

[JimO]

Re: FluView 2010-2011: Weeks 40-4

Re: FluView 2010-2011: Weeks 40-4

Looking at the fluview charts, does seem that the highest hospitalization rates are in the either young and over 65 years. Am I looking at it wrong. Which would be the normal pattern for a flu season. The thing that always is confusing is the CDC says the flu is increasing but by the graph it looks like it is decreasing and then we have the P&I spike????? Very confused
Thanks for posting.

The pattern shown on the chart (showing higher impacts to small children and those >65) is the typical pattern for seasonal flu. The 2009 Pandemic H1N1 (pH1N1) impacted age groups nearly in reverse to that. Until the Holidays, nearly all the flu seen in the U.S. was seasonal flu (AH3N2 or Influenza B) and both were more virulent than is typical. We are just now seeing the impacts of pH1N1 in the %ILI charts while the other two strains are on the decline. Thus, the overall %ILI appears to have either stabilized or declined. This is the leading indicator. P&I deaths actually trail %ILI as an indicator, so even the excess P&I might largely be the result of seasonal flu. What makes it confusing is that we have two overlapping waves - one seasonal and one pH1N1, so the data will likely reflect a hybrid of the two patterns over the next month or so.

It was speculated that the reason those >65 were not affected last season was that pH1N1 was the dominant strain (little to no seasonal flu) and that the older population had been exposed to a similar virus earlier in the 20th century. Unfortunately, data from the UK suggests that the mutated pH1N1, that caused so many serious infections and deaths, is different enough from the 2009 virus to allow it to "escape" both the current vaccine and immunity from prior infections. This is not good news if true because the entire population will be vulnerable -even more than the UK since it appears to have fixed these mutations in the UK.

If my suspicions are correct, we will see a sharp increase in %ILI in the next two weeks. We might see another dip in P&I deaths, but I would expect them to increase about four weeks out at the latest. Near the end of February the mutated strain of pH1N1 will likely become the dominant strain and that is when we could be in crisis mode as the UK was in late December and early January. I sincerely hope I am completely wrong and that is quite possible since I'm not an expert in the field. But, things are shaping up for us to have at least as bad a time of it as we did in the Fall of 2009.

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-5

Re: FluView 2010-2011: Weeks 40-5

During week 5 (January 30-February 5, 2011), influenza activity in the United States increased.

* Of the 7,511 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 2,377 (31.7%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was at the epidemic threshold.(8%)
* Eleven influenza-associated pediatric deaths were reported. Four of these deaths were associated with influenza B viruses, two of these deaths were associated with 2009 influenza A (H1N1) virus, one was associated with an influenza A (H3) virus, and four were associated with an influenza A virus for which the subtype was not determined.
* The proportion of outpatient visits for influenza-like illness (ILI) was 4.6%, which is above the national baseline of 2.5%. Nine of the 10 regions (Regions 1, 2, 3, 4, 5, 6, 7, 8, and 10) reported ILI at or above region-specific baseline levels. Nineteen states experienced high ILI activity; nine states experienced moderate ILI activity; New York City and 10 states experienced low ILI activity; 12 states experienced minimal ILI activity, and the District of Columbia had insufficient data.
* The geographic spread of influenza in 37 states was reported as widespread; nine states reported regional influenza activity; the District of Columbia reported local activity, and Guam, Puerto Rico, the U.S. Virgin Islands, and four states reported sporadic influenza activity.

Two viruses (1%) of the 300 tested showed reduced titers with antiserum produced against A/Perth/16/2009.
One (0.6%) of these 182 viruses showed somewhat reduced titers with antisera produced against B/Brisbane/60/2008

Eleven influenza-associated pediatric deaths were reported to CDC during week 5. Four of these deaths were associated with influenza B viruses, two of these deaths were associated with 2009 influenza A (H1N1) virus, one was associated with an influenza A (H3) virus, and four were associated with an influenza A virus for which the subtype was not determined.

Last week:
Influenza A 1,671 (81.8%)
A (2009 H1N1) 423 (25.3%)
A (subtyping not performed) 530 (31.7%)
A (H3) 718 (43.0%)
Influenza B 373 (18.2%)

This week:
Influenza A 1,845 (77.6%)
A (2009 H1N1) 526 (28.5%)
A (subtyping not performed) 796 (43.1%)
A (H3) 523 (28.3%)
Influenza B 532 (22.4%)
http://www.cdc.gov/flu/weekly/?source=govdelivery

 

[JimO]

Re: FluView 2010-2011: Weeks 40-5

Re: FluView 2010-2011: Weeks 40-5

http://www.cdc.gov/flu/weekly/index.htm#ISTE

From Week 6. Look at the percentage of pediatric cases with no known underlying conditions. Actually, looking back through this season, this is typical. The FluView reports from 2009-10 did not provide this graph, but statements from the CDC suggested that most hospitalized cases and most deaths were those with underlying health conditions.

 

[tetano]

Re: FluView 2010-2011: Weeks 40-5

Re: FluView 2010-2011: Weeks 40-5

2010-2011 Influenza Season Week 6 ending February 12, 2011
During week 6 (February 6-12, 2011), influenza activity in the United States remained elevated.

* Of the 9,448 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 3,306 (35.0%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold.
* Five influenza-associated pediatric deaths were reported. Three of these deaths were associated with 2009 influenza A (H1N1) virus, one was associated with an influenza A virus for which the subtype was not determined, and one was associated with an influenza B virus.
* The proportion of outpatient visits for influenza-like illness (ILI) was 4.5%, which is above the national baseline of 2.5%. All 10 regions reported ILI at or above region-specific baseline levels. Twenty states experienced high ILI activity; nine states experienced moderate ILI activity; New York City and five states experienced low ILI activity, and the District of Columbia and 16 states experienced minimal ILI activity.
* The geographic spread of influenza in 37 states was reported as widespread; 10 states reported regional influenza activity; the District of Columbia reported local activity; Puerto Rico, the U.S. Virgin Islands, and three states reported sporadic influenza activity, and Guam reported no influenza activity.

http://www.cdc.gov/flu/weekly/

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-6

Re: FluView 2010-2011: Weeks 40-6

"Five influenza-associated pediatric deaths were reported to CDC during week 6. Three of these deaths were associated with 2009 influenza A (H1N1) virus, one was associated with an influenza A virus for which the subtype was not determined, and one was associated with an influenza B virus."

One might make the assumption that the 3 pediatric deaths from 2009 A/H1N1 occurred in weeks 4 and 5 since that is when it became most predominant.

Hospitalizations are still rising in all age-groups.

While percent positive appears to be decreasing, it looked that way last week until more data came in. A better gauge is to look at the week prior; it is still heading upward. Last season, the percent positive for influenza peaked at ~38, the year before ~43% (when the predominant virus was 2009 A/H1N1). The percent positive for last week was around 36%, even though it was reported as 31.7%. Fluview does state, "All data are preliminary and may change as more reports are received."

Additionally, ILI appears as though it has peaked, yet data is still coming in from previous weeks. ILI is now appearing to have taken a straighter climb. Based on previous seasons, expect ILI to continue upward in the 7% range, since P&I have exceeded threshold. See: http://www.flutrackers.com/forum/showthread.php?t=153785

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-7

Re: FluView 2010-2011: Weeks 40-7

During week 7 (February 13-19, 2011), influenza activity in the United States remained elevated.

* Of the 9,154 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 2,866 (31.3%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold for the fourth consecutive week.
* Six influenza-associated pediatric deaths were reported bringing to season total to 41. Three of these deaths were associated with an influenza B virus, one was associated with an influenza A (H3) virus, one was associated with a 2009 influenza A (H1N1) virus, and one was associated with an influenza A virus for which the subtype was not determined.
* The proportion of outpatient visits for influenza-like illness (ILI) was 4.9%, which is above the national baseline of 2.5%. All 10 regions reported ILI above region-specific baseline levels. Twenty-one states experienced high ILI activity; six states experienced moderate ILI activity; New York City and 16 states experienced low ILI activity; seven states experienced minimal ILI activity, and the District of Columbia had insufficient data.
* The geographic spread of influenza in 44 states was reported as widespread; four states reported regional influenza activity; the District of Columbia reported local influenza activity; Puerto Rico, the U.S. Virgin Islands, and two states reported sporadic influenza activity, and Guam reported no influenza activity.
http://www.cdc.gov/flu/weekly/

Increasing A(2009 H1N1) laboratory-confirmed, influenza-associated hospitalizations identified in FluSurv-NET.
% hospitalizations increasing for ages 0-17 and 65+

 

[JimO]

Re: FluView 2010-2011: Weeks 40-7

Re: FluView 2010-2011: Weeks 40-7

There is an uncanny resemblance between indicators from Weeks 38 to 40 of 2009 to Weeks 4 to 6 of this season. See comparisons below. The number of total deaths is much lower because pH1N1 hasn't become the dominant strain nationwide (yet) and most states are not reporting adult deaths to the CDC. The current week of positive isolates is always lower than it will be the following week due to late reports from the states. The same goes for pediatric deaths - it's sometimes 3-4 weeks behind.

If it wasn't for the fact that pH1N1 is increasing nationally, I'd say this season would be very close to the 2007-08 season, but I think we will see 2007-08 conditions superimposed upon something similar to the fall of 2009.

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-8

Re: FluView 2010-2011: Weeks 40-8

During week 8 (February 20-26, 2011), influenza activity in the United States remained elevated.

* Of the 7,543 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 2,106 (27.9%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was at the epidemic threshold.
* Fourteen influenza-associated pediatric deaths were reported bringing the season total to 55. Four of these deaths were associated with an influenza B virus, four were associated with a 2009 influenza A (H1N1) virus, two were associated with an influenza A (H3) virus, and four were associated with an influenza A virus for which the subtype was not determined.
* The proportion of outpatient visits for influenza-like illness (ILI) was 4.0%, which is above the national baseline of 2.5%. All 10 regions reported ILI above region-specific baseline levels. Eighteen states experienced high ILI activity; six states experienced moderate ILI activity; New York City and 16 states experienced low ILI activity; 10 states experienced minimal ILI activity, and the District of Columbia had insufficient data.
* The geographic spread of influenza in 44 states was reported as widespread; five states reported regional influenza activity; the District of Columbia and one state reported local influenza activity; Puerto Rico and the U.S. Virgin Islands reported sporadic influenza activity, and Guam reported no influenza activity.

Fourteen influenza-associated pediatric deaths were reported to CDC during week 8. Four of these deaths were associated with an influenza B virus, four were associated with a 2009 influenza A (H1N1) virus, two were associated with an influenza A (H3) virus, and four were associated with an influenza A virus for which the subtype was not determined.
http://www.cdc.gov/flu/weekly/

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-9

Re: FluView 2010-2011: Weeks 40-9

During week 9 (February 27-March 5, 2011), influenza activity in the United States decreased.

* Of the 7,556 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 1,869 (24.7%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold for the sixth consecutive week.
* Five influenza-associated pediatric deaths were reported bringing the season total to 60. Three of these deaths were associated with an influenza B virus and two were associated with an influenza A virus for which the subtype was not determined.
* The proportion of outpatient visits for influenza-like illness (ILI) was 3.1%, which is above the national baseline of 2.5%. Eight of the 10 regions (Regions 1, 2, 3, 4, 5, 7, 8 and 10) reported ILI at or above region-specific baseline levels. Ten states experienced high ILI activity; 12 states experienced moderate ILI activity; nine states experienced low ILI activity; 19 states and New York City experienced minimal ILI activity, and the District of Columbia had insufficient data.
* The geographic spread of influenza in 39 states was reported as widespread; nine states reported regional influenza activity; the District of Columbia and two states reported local influenza activity; Guam and the U.S. Virgin Islands reported sporadic influenza activity, and Puerto Rico did not report.
http://www.cdc.gov/flu/weekly/

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-10

Re: FluView 2010-2011: Weeks 40-10

During week 10 (March 6-12, 2011), influenza activity in the United States decreased.
* Of the 6,384 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 1,346 (21.1%) were positive for influenza.
* The proportion of deaths attributed to pneumonia and influenza (P&I) was at or above the epidemic threshold for the seventh consecutive week.
* Eleven influenza-associated pediatric deaths were reported bringing the season total to 71. Four of these deaths were associated with an influenza B virus, three were associated with 2009 influenza A (H1N1) viruses, two were associated with influenza A (H3N2) viruses, and two were associated with an influenza A virus for which the subtype was not determined.
* The proportion of outpatient visits for influenza-like illness (ILI) was 3.0%, which is above the national baseline of 2.5%. Eight of the 10 regions (Regions 1, 2, 4, 5, 7, 8, 9 and 10) reported ILI at or above region-specific baseline levels. Four states experienced high ILI activity; six states experienced moderate ILI activity; 11 states experienced low ILI activity; 28 states and New York City experienced minimal ILI activity, and the District of Columbia and one state had insufficient data.
* The geographic spread of influenza in 31 states was reported as widespread; 15 states reported regional influenza activity; the District of Columbia and three states reported local influenza activity; Puerto Rico, the U.S. Virgin Islands and one state reported sporadic influenza activity, and Guam reported no influenza activity.
http://www.cdc.gov/flu/weekly/

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-10

Re: FluView 2010-2011: Weeks 40-10

It is important to note that most states, when and if they report, are only reporting pediatric deaths. In the past hour, FluTracker Shiloh, has found several deaths that will probably not show up in states' DoH reports.

Fluview list influenza-associated hospitalizations identified in FluSurv-NET sites by influenza type. A(2009 H1N1) has increased from 23.4% (week 7) to 31.8% (week 10). During this same time period, A(H3N2) has decreased from 76.6% to 68.2% and influenza B has decreased from 15.5% to 14.8%.

Additionally, the percentage of hospitalizations resulting in death has gone from 1.9% (week 7) to 2.2% (week 8).

Reports from FluTrackers such as Shiloh, bring to light some of these cases.

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-11

Re: FluView 2010-2011: Weeks 40-11

During week 11 (March 13-19, 2011), influenza activity in the United States decreased.

Of the 6,144 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 1,158 (18.9%) were positive for influenza.
The proportion of deaths attributed to pneumonia and influenza (P&I) was at or above the epidemic threshold for the eighth consecutive week.
Six influenza-associated pediatric deaths were reported bringing the season total to 77. Two of these deaths were associated with influenza B viruses, two were associated with influenza A (H3N2) viruses, one was associated with 2009 influenza A (H1N1) virus, and one was associated with an influenza A virus for which the subtype was not determined.
The proportion of outpatient visits for influenza-like illness (ILI) was at the national baseline of 2.5%. Six of the 10 regions (Regions 1, 2, 5, 7, 8, and 10) reported ILI at or above region-specific baseline levels. One state experienced high ILI activity; two states experienced moderate ILI activity; 11 states experienced low ILI activity; 35 states and New York City experienced minimal ILI activity, and the District of Columbia and one state had insufficient data.
The geographic spread of influenza in 18 states was reported as widespread; 22 states reported regional influenza activity; the District of Columbia and seven states reported local influenza activity; Guam, Puerto Rico, the U.S. Virgin Islands and three states reported sporadic influenza activity.
http://www.cdc.gov/flu/weekly/

 

[gsgs]

Re: FluView 2010-2011: Weeks 40-11

Re: FluView 2010-2011: Weeks 40-11

see here, how much similar this season was so far in timing
to the 2008/9 season

the (double-)peak came one week earlier this season
(after the thanksgiving-benchmark)
and was 28% higher
Christmas was shared by 2 weeks


(population-weighted) percentage of doctor visits that are due to ILI

 

[Missouriwatcher]

Re: FluView 2010-2011: Weeks 40-12

Re: FluView 2010-2011: Weeks 40-12

During week 12 (March 20-26, 2011), influenza activity in the United States decreased.

Of the 5,319 specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division, 737 (13.9%) were positive for influenza.
The proportion of deaths attributed to pneumonia and influenza (P&I) has been at or above the epidemic threshold for the ninth consecutive week.
Twelve influenza-associated pediatric deaths were reported, bringing the season total to 89. Four of these deaths were associated with influenza B viruses; four were associated with 2009 influenza A (H1N1) viruses; one was associated with influenza A (H3N2) virus, and three were associated with an influenza A virus for which the subtype was not determined.
The proportion of outpatient visits for influenza-like illness (ILI) was 2.0%, below the national baseline of 2.5%. Two of the 10 regions (Regions 2 and 10) reported ILI at or above region-specific baseline levels. One state experienced high ILI activity; three states experienced low ILI activity; 46 states and New York City experienced minimal ILI activity, and the District of Columbia had insufficient data.
The geographic spread of influenza in 10 states was reported as widespread; 21 states reported regional influenza activity; the District of Columbia and 12 states reported local influenza activity, and Guam, Puerto Rico, the U.S. Virgin Islands and six states reported sporadic influenza activity.
http://www.cdc.gov/flu/weekly/