Flu update: May through August

  
In May, June, July and August 2011, Influenza activity was low in North America, Europe, Northern Asia, Middle East and North Africa. Tepid latitudes of Northern hemisphere remained at baseline inter-seasonal levels.

The 2011 influenza season in South Africa peaked in the end of June. The majority of samples were identified as 2009 H1N1 virus. Flu levels were still moderate in early July but illness activity became low by the end of July.

Dominican Republic, Cuba, Honduras and Brazil observed moderate activity (peak was in the end of June/beginning of July). Columbia had active circulation of 2009 H1N1 virus, but there were no new cases in July and August. Illness levels in Peru and Bolivia also returned to low levels.

Flu activity in August was low in countries of Western Africa (Ghana, Cameroon and Senegal), and Southern Asia (India, Bangladesh, Thailand, and Singapore).  Google flu trends predicted increased activity for South Africa and Chile in June-July and Uruguay in July-August. WHO data showed that flu levels returned to low in South Africa, but started to increase for Chile, Uruguay and Argentina marking the peak of the season.

In Australia, influenza-like illness consultations and laboratory-confirmed cases continue to increase.
The flu season started in the end of April, rates slightly declined in mid May but kept increasing since.  The most common virus was influenza A(H1N1)2009 but influenza B was also prevalent, unevenly distributed across the country.

According to the ESR Kenepuru Science Centre and the WHO, flu incidents in New Zealand increased from mid-May through the end of July, but decreased during the first two weeks of August. ILI activity in New Zealand remained around expected levels and the majority of viruses detected have been influenza B.

See the latest CDC  Global and WHO updates for more.

Flu update: Have we passed the peak?

According to WHO, the highest influenza rates were in Asia, with notable increases in respiratory disease activity in Singapore and Hong Kong, and the majority of cases tested positive for 2009 H1N1. Influenza activity appears to have peaked in the majority of North African and Middle Eastern countries with the exception of Algeria, where rates increased. The percentage of respiratory specimens testing positive for influenza was also high in Pakistan, Iran and Oman. Influenza cases in southern China decreased from its peak earlier this season.Although influenza activity was sparse in the tropical Americas and sub-Saharan Africa, it increased in Madagascar. Influenza activity remained low in the temperate Southern Hemisphere.
 According to the Public Health Agency of Canada, influenza activity increased slightly, but remained below the peak observed earlier this season.

In US, the following ILI activity levels were experienced:

• Twenty-one states (Alabama, Arkansas, California, Colorado, Georgia, Hawaii, Idaho, Illinois, Indiana, Kansas, Louisiana, Missouri, New Jersey, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and West Virginia) experienced high ILI activity.
• Six states (Alaska, Arizona, Connecticut, Massachusetts, Pennsylvania, and Utah) experienced moderate ILI activity.
• New York City and 16 states (Delaware, Florida, Kentucky, Maryland, Minnesota, Mississippi, Nebraska, Nevada, New York, North Dakota, Ohio, Oregon, South Dakota, Washington, Wisconsin, and Wyoming) experienced low ILI activity.
• Minimal ILI activity was experienced by seven states (Iowa, Maine, Michigan, Montana, New Hampshire, Rhode Island, and Vermont).
  
  

In Europe, activity moved past its peak, although it was still intense in Luxembourg, Georgia and the Siberian region of the Russian Federation (source).

Intensity

Geographic Spread

Impact

Sentinel swabs

Percentage positive

Dominant type

ILI per 100,000

ARI per 100,000

Sentinel SARI

Virology graph and pie chart

Albania

High

Local

Moderate

37

5.4%

None

494.3

(graphs)

Click here

Armenia

Medium

Local

Moderate

5

0%

None

0.0

(graphs)

91.2

(graphs)

sari

Click here

Austria

Medium

Widespread

Low

69

65.2%

Type A, Subtype pH1N1

0.0

(graphs)

35.2

(graphs)

Click here

Azerbaijan

Low

Sporadic

Low

22

0%

None

314.2

(graphs)

Click here

Belarus

Medium

Local

Moderate

29

51.7%

Type A, Subtype pH1

1756.0

(graphs)

Click here

Belgium

Medium

Widespread

50

62.0%

Type B and Type A, Subtype pH1N1

328.2

(graphs)

1573.2

(graphs)

Click here

Bosnia and Herzegovina

Type A, Subtype pH1

(graphs)

Click here

Bulgaria

Medium

Regional

10

70.0%

Type A, Subtype pH1

0.0

(graphs)

1339.0

(graphs)

Click here

Croatia

High

Widespread

Low

Type A, Subtype pH1

221.2

(graphs)

Click here

Cyprus

Low

Local

Low

1.5 *

(graphs)

8.0 *

(graphs)

Click here

Czech Republic

Medium

Widespread

29

82.8%

Type A, Subtype pH1N1

226.1

(graphs)

1435.3

(graphs)

Click here

Denmark

Medium

Widespread

38

13.2%

None

(graphs)

0.0

(graphs)

Click here

England

Low

Sporadic

96

14.6%

Type A and B

12.1

(graphs)

390.9

(graphs)

Click here

Estonia

Medium

Widespread

40

15.0%

Type A, Subtype pH1

18.4

(graphs)

437.3

(graphs)

Click here

Finland

Widespread

48

33.3%

Type B and Type A, Subtype pH1N1

0.0

(graphs)

0.0

(graphs)

Click here

France

Medium

Widespread

Low

175

45.7%

Type B and Type A, Subtype pH1N1

0.0

(graphs)

2369.6

(graphs)

Click here

Georgia

Very High

Widespread

Severe

48

93.8%

Type B and Type A, Subtype pH1

1454.7

(graphs)

sari

Click here

Germany

Medium

Regional

242

50.8%

Type A, Subtype pH1N1

0.0

(graphs)

1309.0

(graphs)

Click here

Greece

High

Widespread

37

59.5%

Type A, Subtype pH1N1

399.9

(graphs)

0.0

(graphs)

Click here

Hungary

Medium

Widespread

Moderate

143

11.9%

Type A, Subtype pH1

475.6

(graphs)

0.0

(graphs)

Click here

Iceland

Medium

Regional

Moderate

0

0%

75.2

(graphs)

0.0

(graphs)

Click here

Ireland

Medium

Regional

Low

47

31.9%

Type B

36.2

(graphs)

0.0

(graphs)

Click here

Israel

Medium

Widespread

Moderate

41

34.2%

Type A and B

35.0

(graphs)

Click here

Italy

High

Widespread

Moderate

113

55.8%

Type A, Subtype pH1N1

768.5

(graphs)

0.0

(graphs)

Click here

Kazakhstan

Medium

Local

Moderate

14

92.9%

None

1.9

(graphs)

365.9

(graphs)

sari

Click here

Kyrgyzstan

Low

Sporadic

Low

10

60.0%

Type A and B

8.6

(graphs)

45.9

(graphs)

sari

Click here

Latvia

Medium

Widespread

9

33.3%

Type B

(graphs)

Click here

Lithuania

High

Widespread

Low

85.8

(graphs)

660.7

(graphs)

Click here

Luxembourg

58

58.6%

Type B and Type A, Subtype pH1

(graphs)

Click here

Malta

Low

Local

Low

9.2 *

(graphs)

0 *

(graphs)

Click here

Netherlands

Medium

Widespread

32

53.1%

Type B

60.4

(graphs)

0.0

(graphs)

Click here

Northern Ireland

Low

Sporadic

10

10.0%

Type B

29.9

(graphs)

359.2

(graphs)

Click here

Norway

Low

Widespread

7

42.9%

Type B and Type A, Subtype pH1

120.0

(graphs)

0.0

(graphs)

Click here

Poland

Medium

Regional

102

23.5%

Type A, Subtype pH1

171.8

(graphs)

0.0

(graphs)

Click here

Portugal

Low

Sporadic

3

0%

Type A, Subtype pH1

31.5

(graphs)

0.0

(graphs)

Click here

Republic of Moldova

Medium

Local

Moderate

84

57.1%

Type B and Type A, Subtype pH1N1

27.0

(graphs)

470.0

(graphs)

sari

Click here

Romania

High

Widespread

Moderate

30

83.3%

Type B and Type A, Subtype pH1N1

41.6

(graphs)

1260.4

(graphs)

sari

Click here

Russian Federation

High

Widespread

Moderate

66

39.4%

Type A, Subtype pH1

38.4

(graphs)

1096.3

(graphs)

sari

Click here

Scotland

Low

Local

Low

45

22.2%

Type B

2.2

(graphs)

253.2

(graphs)

Click here

Serbia

High

Regional

Moderate

1

100.0%

Type A, Subtype pH1N1

204.6

(graphs)

sari

Click here

Slovakia

Medium

Local

Low

23

65.2%

Type A, Subtype pH1

487.9

(graphs)

2514.5

(graphs)

Click here

Slovenia

Medium

Widespread

23

65.2%

Type B and Type A, Subtype pH1

69.6

(graphs)

1499.3

(graphs)

Click here

Spain

Medium

Regional

246

31.7%

Type B

113.6

(graphs)

0.0

(graphs)

Click here

Sweden

High

Widespread

Low

33

27.3%

Type B

19.5

(graphs)

0.0

(graphs)

Click here

Switzerland

Medium

Widespread

65

76.9%

Type B and Type A, Subtype pH1

276.8

(graphs)

Click here

Turkey

Medium

Local

Moderate

107

40.2%

None

(graphs)

Click here

Ukraine

Medium

Local

Low

4

25.0%

Type A and B

5.2 *

(graphs)

674.7

(graphs)

sari

Click here

Wales

Low

Sporadic

Low

6.2

(graphs)

0.0

(graphs)

Click here

Europe

2291

42.2%

Click here

Flu Season is not over yet, but February marks the peak

As of mid February 2011, influenza activity in the United States remains elevated, but it appears to have peaked in the majority of European, North African and Middle Eastern countries.

• There were more outpatient visits for influenza-like illness (ILI): 4.5% vs the national baseline of 2.5%, it was above region-specific baseline levels in all US regions. 
• • Twenty states (Alabama, Arkansas, Colorado, Georgia, Idaho, Indiana, Louisiana, Maryland, Missouri, New Jersey, New Mexico, New York, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Utah, Virginia, and West Virginia) experienced high ILI activity.
  • Nine states (California, Florida, Hawaii, Illinois, Kansas, Kentucky, Mississippi, Pennsylvania, and Wyoming) experienced moderate ILI activity.
  • New York City and five states (Arizona, Massachusetts, Nebraska, Nevada, and Wisconsin) experienced low ILI activity.
  • Minimal ILI activity was experienced by the District of Columbia and 16 states (Alaska, Connecticut, Delaware, Iowa, Maine, Michigan, Minnesota, Montana, New Hampshire, North Dakota, Ohio, Oregon, Rhode Island, South Dakota, Vermont, and Washington).
• 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.  

Global flu activity (see CDC page for current information), was most prominent in the tropical regions of Asia. From February, cases of respiratory disease were high in Singapore and Hong Kong, and 90% of influenza-positive samples were 2009 H1N1. Influenza activity continued to rise in southern China, where 46% of ILI specimens in Week 5 tested positive for influenza, a 3% increase from Week 4. 2009 H1N1 was the predominant subtype.

According to WHO, Madagascar reported an increase in influenza activity, with the co-circulation of influenza B and A (H3N2). There was little influenza activity reported in the tropical regions of the Americas or in sub-Saharan Africa. 

Influenza activity in the majority of North African and Middle Eastern countries appears to have peaked, except for Algeria, where flu activity increased. The percentage of influenza-positive respiratory specimens was also high in Pakistan, Iran and Oman, where 2009 H1N1 and type B viruses co-circulated in relatively equal numbers.

According to the Public Health Agency of Canada, influenza activity increased slightly in Week 5, but remained below the peak reported earlier this season. The percentage of influenza-positive respiratory samples increased from 17% in Week 4 to 19% in Week 5. Since the beginning of the influenza season, 88% of subtyped influenza A specimens have been influenza A (H3N2).

According to the China National Influenza Center, influenza activity rose in recent weeks in northern China. In Week 5, 21% of influenza-like illness (ILI) specimens were influenza-positive, and 2009 H1N1 viruses were predominant. WHO reported that Mongolia saw an increase in 2009 H1N1 virus detections, while Japan saw a sharp increase in ILI activity.

Activity in the Southern Hemisphere remained low.

In Europe, 2 countries (Georgia and Luxembourg) and the Siberian region of the Russian Federation reported very high intensity of influenza activity; 8 countries reported high intensity; 27 reported medium intensity and 4 countries, low intensity. 23 countries reported widespread activity. Of the 25 countries reporting on the impact of influenza on health care systems, 1 (Georgia) reported severe impact; 14 countries reported moderate impact and 10, low impact.

Of the 41 countries reporting on consultation rates for ILI and ARI, 8 (Albania, Belarus, the Czech Republic, Iceland, Kazakhstan, the Republic of Moldova, Serbia and Slovakia) reported increases while 6 (Ireland, Israel, Malta, Norway, Spain and the United Kingdom (England)) reported decreases. Influenza activity has apparently passed its peak in 24 countries in this region. In general, the highest consultation rates were reported for children aged 0–4 and 5–14 years.

WHO/Europe received sentinel surveillance data on hospitalized SARI cases from 9 countries (Armenia, Georgia, Kazakhstan, Kyrgyzstan, Romania, the Republic of Moldova, the Russian Federation, Serbia and Ukraine). Sentinel SARI hospitalizations are at the highest levels observed for the season so far in Georgia and Serbia. In Georgia, however, outpatient clinical consultation rates declined from week 5 to week 6, while the relative percentage of both SARI and ILI specimens testing positive for influenza B increased. Sentinel SARI hospitalizations in Kazakhstan, Kyrgyzstan, Romania and the Russian Federation have declined somewhat from observed peaks in weeks 3–5, but remain notably elevated above pre-season levels, with 30–50% of sentinel SARI specimens testing positive for influenza in each of these countries. Sentinel SARI admissions in the Republic of Moldova and Ukraine are at levels below prior peaks. Nevertheless, a significant percentage of sentinel SARI specimens continue to test positive for influenza, and the proportion of influenza A detections in sentinel SARI specimens in Ukraine increased in week 6. Further information on the sentinel SARI surveillance systems represented in the EuroFlu bulletin can be found in the “Overview of sentinel SARI systems in EuroFlu”.

Table and graphs (Europe) Intensity Geographic Spread Impact Sentinel swabs Percentage positive Dominant type ILI per 100,000 ARI per 100,000 Sentinel SARI Virology graph and pie chart Albania High Local Moderate 78 16.7% Type A, Subtype pH1 and H3 503.6 (graphs) Click here Armenia Medium Local Moderate 3 33.3% None 0.0 (graphs) 81.4 (graphs) sari Click here Austria Medium None Low 70 68.6% Type A, Subtype pH1N1 0.0 (graphs) 33.2 (graphs) Click here Azerbaijan Low Sporadic Low 17 0% None 292.7 (graphs) Click here Belarus Medium Local Moderate 33 30.3% Type A, Subtype pH1 1938.6 (graphs) Click here Belgium Medium Widespread 53 62.3% Type B and Type A, Subtype pH1 391.1 (graphs) 1695.1 (graphs) Click here Bosnia and Herzegovina Type A, Subtype pH1 (graphs) Click here Bulgaria Medium Regional 14 28.6% Type A, Subtype pH1 0.0 (graphs) 1439.3 (graphs) Click here Croatia High Widespread Low Type A, Subtype pH1 186.6 (graphs) Click here Czech Republic Medium Widespread 29 75.9% Type B and Type A, Subtype pH1N1 296.7 (graphs) 1583.2 (graphs) Click here Denmark Medium Widespread 51 25.5% None (graphs) 0.0 (graphs) Click here England Low Sporadic 137 11.7% Type A and B 18.4 (graphs) 424.7 (graphs) Click here Estonia Medium Widespread 55 34.6% Type A, Subtype pH1N1 23.1 (graphs) 502.3 (graphs) Click here Finland Widespread 62 71.0% Type B and Type A, Subtype pH1 0.0 (graphs) 0.0 (graphs) Click here France Medium Widespread Low 232 41.4% Type B and Type A, Subtype pH1N1 0.0 (graphs) 2824.4 (graphs) Click here Georgia Very High Widespread Severe 57 91.2% Type B and Type A, Subtype pH1 1627.6 (graphs) sari Click here Germany Medium Regional 305 61.0% Type A, Subtype pH1N1 0.0 (graphs) 1342.3 (graphs) Click here Greece High Widespread 18 72.2% Type A, Subtype pH1N1 361.0 (graphs) 0.0 (graphs) Click here Hungary High Widespread Moderate 162 9.3% Type A, Subtype pH1 587.9 (graphs) 0.0 (graphs) Click here Iceland Medium Regional Moderate 0 0% 57.6 (graphs) 0.0 (graphs) Click here Ireland Medium Widespread Low 53 39.6% Type B 50.3 (graphs) 0.0 (graphs) Click here Israel Medium Widespread Moderate 58 53.5% Type A and B 52.8 (graphs) Click here Italy High Widespread Moderate 230 36.5% Type A, Subtype pH1N1 965.4 (graphs) 0.0 (graphs) Click here Kazakhstan Medium Local Moderate 44 27.3% None 3.1 (graphs) 422.3 (graphs) sari Click here Kyrgyzstan Low None Low 14 35.7% Type A and B 9.3 (graphs) 82.4 (graphs) sari Click here Latvia Medium Widespread 21 47.6% Type B and Type A, Subtype pH1 (graphs) Click here Lithuania 14 57.1% Type B and Type A, Subtype pH1 (graphs) Click here Luxembourg Very High Widespread 108 62.0% Type B and Type A, Subtype pH1 10.2 * (graphs) 27.9 * (graphs) Click here The former Yugoslav Republic of Macedonia None (graphs) Click here Malta Low Local Low 0 0% 3.6 * (graphs) 0 * (graphs) Click here Netherlands Medium Widespread 31 29.0% Type B 70.9 (graphs) 0.0 (graphs) Click here Northern Ireland Low Local Type B 35.6 (graphs) 372.6 (graphs) Click here Norway Medium Widespread 25 60.0% Type B 145.8 (graphs) 0.0 (graphs) Click here Poland Medium Regional 114 29.8% Type A, Subtype pH1 180.8 (graphs) 0.0 (graphs) Click here Portugal Medium Widespread 8 50.0% Type A, Subtype pH1 50.0 (graphs) 0.0 (graphs) Click here Republic of Moldova Medium Local Moderate 69 66.7% Type B and Type A, Subtype pH1N1 37.8 (graphs) 394.3 (graphs) sari Click here Romania Medium Widespread Moderate 55 45.5% Type B and Type A, Subtype pH1N1 93.8 (graphs) 2855.0 (graphs) sari Click here Russian Federation High Widespread Moderate 66 45.5% Type A, Subtype pH1 57.0 (graphs) 1295.9 (graphs) sari Click here Scotland Medium Local Low 48 41.7% Type B 8.9 (graphs) 262.1 (graphs) Click here Serbia High Regional Moderate 23 65.2% Type A, Subtype pH1N1 218.2 (graphs) sari Click here Slovakia Medium Regional Moderate 572.5 (graphs) 2820.6 (graphs) Click here Slovenia Medium Widespread 39 82.1% Type B and Type A, Subtype pH1 69.6 (graphs) 1711.9 (graphs) Click here Spain Medium Regional 340 36.5% Type B 152.4 (graphs) 0.0 (graphs) Click here Sweden High Widespread Low 55 72.7% Type B 12.6 (graphs) 0.0 (graphs) Click here Switzerland Medium Widespread 312.0 (graphs) Click here Turkey Medium Local Moderate 304 50.0% None (graphs) Click here Ukraine Medium Local Low 14 28.6% Type B and Type A, Subtype pH1 4.6 * (graphs) 641.4 (graphs) sari Click here Wales Low Sporadic Low 8.3 (graphs) 0.0 (graphs) Click here Europe 3109 44.2% Click here Preliminary data Intensity: Low = no influenza activity or influenza activity at baseline level; Medium= usual levels of influenza activity; High = higher than usual levels of influenza activity; Very high = particularly severe levels of influenza activity. Percentage positive: percentage of sentinel swabs that tested positive for influenza A or B Dominant type: this assessment is based on data from sentinel and non-sentinel sources ARI: acute respiratory infection ILI: influenza-like illness Population: per 100,000 population *: the value in the table for these countries reflects the percent (e.g. from 0.0 to 100.0) of total outpatient encounters that were due to ILI/ARI rather than a consultation rate per 100,000