Severity

A subset of Member States monitor severe disease related to influenza virus infection by surveillance of 1) hospitalized laboratory-confirmed influenza cases in ICUs (n=12), or other wards (n=8), or 2) severe acute respiratory infections (SARI; n=16).

The majority of severe cases reported this season have been due to influenza type B and have occurred in persons above the age of 15 years. In laboratory-confirmed influenza cases in ICU, slightly more cases were infected with influenza type A compared to type B viruses (n=4 908 and 4 433, respectively).

In laboratory-confirmed influenza cases reported in wards other than ICUs, influenza type B viruses were detected more frequently than influenza type A viruses (11 122 vs. 6 915), and more cases occurred among those older than 64 years compared with patients in the 15–64 years age group (10 273 vs. 5 506).

1.1) Hospitalized laboratory-confirmed influenza cases – Intensive care units (ICU)

Since week 40/2017, 13 countries have reported laboratory-confirmed influenza cases admitted to either all ICUs in the country or a set of sentinel ICUs (Table).

Numbers of reported hospitalized laboratory-confirmed influenza cases in ICUs remained low in week 19/2018, reflecting the decreasing influenza activity in the Region. There were 13 laboratory-confirmed influenza cases in ICUs: 12 in the United Kingdom and 1 in Romania. For weeks 17/2018 and 18/2018 17 and 11 cases were reported, respectively, by the same countries.

Since week 40/2017, type A influenza viruses have been detected in 53% and type B in 47% of cases in ICUs. Of 1 878 subtyped influenza A viruses, 58% were A(H1N1)pdm09 and 42% A(H3N2). Of 5 774 cases with known age, 44% were 15–64 years old and 48% were aged 65 years and older.

Laboratory-confirmed ICU admitted cases* by country, cumulatively weeks 40/2017–19/2018

Country

Total Cases

A unsub.

A(H1N1) pdm09

A(H3N2)

B total

0-4

yrs

5-14

yrs

15-64

Yrs

>64

yrs

UNK

Czech Republic

308

45

64

6

193

12

10

130

156

0

Denmark

544

99

55

40

350

13

8

191

332

0

Finland

64

0

4

29

31

1

1

19

43

0

France

2 914

1 230

519

59

1 106

72

48

1 376

1 364

54

Ireland

166

42

16

28

80

18

16

62

70

0

Netherlands

15

5

0

0

10

0

0

8

7

0

Romania

55

1

26

1

27

4

2

25

24

0

Russian Federation

8

0

2

6

0

0

0

3

5

0

Spain

1 252

310

149

158

635

103

36

545

568

0

Sweden

443

132

9

14

288

10

19

184

230

0

Ukraine

59

1

1

2

55

16

20

23

0

0

United Kingdom

3 513

1 154

243

447

1 658

0

0

0

0

3 513

TOTAL

9 341

3 030

1 088

790

4 433

249

160

2 566

2 799

3 567

 A unsub.= type A unsubtyped; *from either sentinel hospitals or all hospitals per country 

1.2) Hospitalized laboratory-confirmed influenza cases – other wards

For week 19/2018, 7 cases were reported from other wards. Numbers of cases in other wards decreased in week 19/2018 compared to week 18/2018 (n=11).

Since week 40/2017, 8 countries have reported laboratory-confirmed hospitalized influenza cases in other wards (Table). The majority (62%) of these cases were infected by influenza type B viruses and 60% of all cases were in patients aged 65 years and older.

Laboratory-confirmed hospitalised cases in other wards* by country, cumulatively weeks 40/2017–19/2018

Country

Total Cases

A unsub.

A(H1N1) pdm09

A(H3N2)

B total

0-4

yrs

5-14

yrs

15-64

yrs

>64

yrs

UNK

Czech Republic

344

67

88

6

183

6

4

133

201

0

Denmark

7 978

1 244

506

702

5 526

429

285

2 656

4 608

0

Ireland

4 395

1 268

214

485

2 428

587

418

1 258

2 130

2

Romania

101

3

43

6

49

23

13

51

14

0

Russian Federation

359

0

50

184

125

80

33

199

47

0

Slovakia

4

2

1

0

1

0

0

4

0

0

Spain

4 597

1 247

255

520

2 575

247

52

1 030

3 268

0

Ukraine

259

10

6

8

235

35

44

175

5

0

TOTAL

18 037

3 841

1 163

1 911

11 122

1 407

849

5 506

10273

2

A unsub.= type A unsubtyped; *from either sentinel hospitals or all hospitals per country 

 

2. SARI surveillance

Since week 40/2017, SARI cases have been reported by 16 countries, the majority being located in the eastern part of the Region.

For week 19/2018, 296 SARI cases were reported by 10 countries, most (43%) by the Republic of Moldova. 61 specimens were tested for influenza viruses with 2 being positive, indicating a decrease compared to week 18/2018 when 8 of 88 specimens tested positive.

For SARI cases testing positive for influenza virus, type B viruses have been the most common; 57% overall for weeks 40/2017–19/2018. Of the 880 influenza type A infected cases for which subtyping was performed, 66% were infected by A(H1N1)pdm09 viruses.

Mortality monitoring

Data from 20 EU/EEA Member States or regions reporting to the EuroMOMO project were received for week 19/2018 and included in pooled analyses. Mortality has been significantly elevated in many European countries over the past months, mainly affecting elderly people. However, mortality now appears be have returned to normal expected levels in all the participating countries.