Bulletin of the World Health Organization

The challenges of global case reporting during pandemic A(H1N1) 2009

Stephanie Williams, Julia Fitzner, Angela Merianos, Anthony Mounts & for the Case-based Surveillance Evaluation Group

Volume 92, Number 1, January 2014, 60-67

Table 1. Earliera cases of A(H1N1) pandemic influenza, by region, 2009

Characteristic Region
Americasb Europec Asiad Northern Africa and Middle Easte Sub-Saharan Africaf All
No. of countries 6 38 30 5 2 81
No. of case records (% of all early cases) 464 (12) 1961 (53) 1026 (28) 44 (1) 215 (6) 3710
No. with age data (% complete) 464 (100) 1937 (99) 1018 (99) 41 (93) 212 (99) 3672 (99)
Median age in years (IQR) 17 (11–28) 24 (17–34) 23 (14–36) 27 (21–35) 18 (8–25) 23 (14–33)
No. with sex data (%) 460 (99) 1942 (99) 1026 (100) 43 (98) 215 (100) 3686 (99)
Males (%) 230 (50) 1046 (54) 544 (53) 19 (44) 109 (49) 1945 (53)
No. with imported case data (% complete) 153 (33) 1901 (97) 975 (95) 25 (57) NA 3054 (82)
No. imported (%) 75 (50) 1377 (72) 502 (51) 20 (80) NA 1974 (65)
No. with hospital data (% complete) 374 (81) 1548 (79) 920 (90) 28 (64) 110 (51) 2980 (80)
No. hospitalized (%) 131 (35) 513 (33) 667 (73) 23 (82) 2 (2) 1336 (45)
No. of hospitalized cases with age data 131 510 662 23 2 1328
Median age in years (IQR) 21 (10–31) 24 (18–34) 23 (14–37) 29 (24–42) 14 (4–24) 23 (15–35)
No. with fatal outcome data (% complete) 295 (64) NA 43 (4) 2 (5) 105 (49) 445 (12)
No. of fatal cases (%) 2 (0.6) NA 0 0 0 2 (0.5)

IQR, interquartile range; NA, not available.

a Defined as the first 110 cases by date of symptom onset.

b Bahamas, Colombia, Costa Rica, Cuba, Panama and the United States of America.

c Andorra, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, Montenegro, the Netherlands, Norway, Poland, Portugal, Romania, the Russian Federation, Serbia, Slovakia, Spain, Sweden, The former Yugoslav Republic of Macedonia, Turkey, Ukraine and the United Kingdom of Great Britain and Northern Ireland.

d Australia, Bangladesh, Brunei Darussalam, Cambodia, China (with Hong Kong Special Administrative Region [SAR] and Macao SAR), the Cook Islands, the Federated States of Micronesia, Fiji, India, Japan, Kiribati, Laos, Malaysia, Micronesia (Federated States of) Mongolia, Myanmar, Nepal, New Zealand, Palau, Papua New Guinea, the Philippines, the Republic of Korea, Samoa, Singapore, the Solomon Islands, Thailand, Tonga, Vanuatu, Viet Nam.

e Israel, Lebanon, Morocco, Qatar and the West Bank and Gaza Strip.

f Rwanda and South Africa.

Note: Case data missing date of onset were excluded. Therefore, not all countries that contributed data are listed. Geographic grouping was used rather than the official WHO regions as this better reflects the spread of the virus.