Volume 18, Number 9—September 2012
Dispatch
Demographic Shift of Influenza A(H1N1)pdm09 during and after Pandemic, Rural India
, Wayne Sullender, Karen Fowler, Vivek Gupta, Marc-Alain Widdowson, Anand Krishnan, and Renu B. LalTable 1
Demographic data for persons under surveillance and incidence of febrile ARI and influenza A(H1N1)pdm09 during pandemic and postpandemic periods, Ballabgarh, India*
| Demographics and test results | Pandemic period, November 2009–January 2010 | Postpandemic period, August–October 2010 |
|---|---|---|
| Mean no. persons under surveillance (person-years) | 7,340 (1,835) | 16,396 (4,134) |
| No. febrile ARI episodes (incidence rate/1,000 person-years) | 1,515 (826) | 4,933 (1,203) |
|
No. (%) persons tested for influenza |
1,094 (72) | 3,907 (79) |
|
No. (%) positive for influenza |
265 (24) | 902 (23)† |
|
No. (%) positive for influenza A(H1N1)pdm09 |
231 (21) | 506 (13) |
|
No. (%) positive for influenza B |
34 (3) | 377 (10) |
|
Influenza incidence rate/1,000 person-years |
205‡ | 278 |
| Median age, y (interquartile range) | ||
|
All persons with influenza |
9 (4–17) | 15 (6–30)§ |
|
Persons with influenza A(H1N1)pdm09 |
9 (5–18) | 18 (7–32)§ |
|
Persons with Influenza B |
7.5 (4–16) | 13 (5–27) |
*ARI, acute respiratory infection.
†Total no. positive during postpandemic period included 18 persons with influenza A (H3N2) infection and 1 person co-infected with influenza B and A(H1N1)pdm09.
‡The rate of influenza positivity of sampled febrile ARI case-patients was adjusted to unsampled case-patients assuming similar characteristics for the 2 groups.
§Wilcoxon rank-sum test, p<0.001.
