Table 2.
Proportion of identified severe acute respiratory infections case-patients with complete information for selected variables, pilot case–control study for influenza vaccine effectiveness in Central-America, 2012 (n = 1,186)
| 6 months − 11 years (n = 777) | ≥60 years (n = 409) | |||
|---|---|---|---|---|
| Influenza cases | Controls | Influenza cases | Controls | |
| n = 212 | n = 565 | n = 130 | n = 279 | |
| Age | 100 % | 100 % | 100 % | 100 % |
| Gender | 100 % | 100 % | 100 % | 100 % |
| Clinical information | ||||
| Date of onset of illness | 100 % | 100 % | 100 % | 100 % |
| Date of specimen collection | 92 % | 95 % | 95 % | 100 % |
| Preexisting conditions (yes/no) | 67 % | 61 % | 88 % | 87 % |
| Vaccination information | ||||
| Vaccination status for current influenza vaccinea | 88 % | 88 % | 82 % | 91 % |
| Date of current influenza vaccine receipt | 100 % | 100 % | 100 % | 100 % |
| Vaccination status for a second annual dose among children 6 months–9 yearsb | 67 % (121/193) | 57 % (289/503) | NAc | NA |
| Prior season influenza vaccination | 96 % | 96 % | 84 % | 94 % |
| Pneumococcal vaccination statusd | 80 % | 86 % | 34 % | 19 % |
| Number of complete records for key variables for vaccine effectiveness analysese | 170 (80 %) | 471 (83 %) | 100 (77 %) | 253 (91 %) |
| Number of complete records for all variables collectedf | 151 (71 %) | 458 (81 %) | 34 (26 %) | 51 (18 %) |
aFor receipt of at least one dose among children and older adults and after active/enhanced vaccination status ascertainment
bWHO recommends 2 doses among children 6 months–9 years vaccinated for the first time
cNA = Not applicable
dVaccination up-to-date (yes/no) according to local recommendations
eDefined as age, gender, dates of onset of symptoms and specimen collection, current vaccine status and date, presence of at least one preexisting condition, and country
fKey variables, pneumococcal vaccination and prior influenza vaccination