Estimated incidence of influenza-virus-associated severe pneumonia in children in El Salvador, 2008–2010
Wilfrido Clara, Julio Armero, David Rodriguez, Celina de Lozano, Luis Bonilla, Percy Minaya, Rafael Chacón, Jorge Jara, Natalia Blanco, Marc-Alain Widdowson, Joseph Bresee, Xiyan Xu, Alexander Klimov, Eduardo Azziz-Baumgartner & Nivaldo Linares-Perez
Volume 90, Number 10, October 2012, 756-763
Table 3. Variables used to estimate the incidence of influenza-virus-associated severe pneumonia among children aged < 5 years living in the catchment area of San Juan de Dios Hospital, Santa Ana, El Salvador, 2008–2010
| Variable | 2008 | 2009 | 2010 | 2008–2010 |
|---|---|---|---|---|
| Case patients identified at San Juan de Dios Hospital, no. | 495 | 1367 | 692 | 2554 |
| Case patients tested for respiratory viruses, no. | 153 | 217 | 238 | 608 |
| Case patients positive for influenza virus | ||||
| Detected no., (%), (95% CI) | 11 (7) (3–11) | 21 (10) (6–14) | 5 (2) (0.2–4) | 37 (6) (4–8) |
| Imputed no. | 33 | 165 | 14 | 212 |
| Census population aged < 5 years in catchment areaa | 36 858 | 37 016 | 37 205 | 111 079 |
| Census population that visits the sentinel site when ill, %b | 63 | 63 | 63 | 63 |
| Days when surveillance was performed, no., (%)c | 343 (94) | 340 (93) | 339 (93) | 1022 (93) |
| Adjusted census population (person–years) | 21 827 | 21 688 | 21 798 | 65 081 |
CI, confidence interval.
a Data are from the National VI Population and V Household Census 2007 of El Salvador.
b Data are from the sentinel site health-care service utilization survey performed in Santa Ana during November–December 2009.
c Percentages represent the proportion of days when surveillance was conducted in one year (365 days) or, for the last column, in three years (1095 days).