Table 2.
Estimates of influenza vaccine effectiveness for children aged 6–24 months, single and two dose vaccination, REVELAC-i, five South American countries, 2013–2017.
| Cases |
Controls |
aVE % (95%CI) |
|||
|---|---|---|---|---|---|
| Vaccinated (%) | Unvaccinated (%) | Vaccinated (%) | Unvaccinated (%) | ||
| Any influenza virus | |||||
| Two-dose vaccination | 89 (27) | 241 (73) | 522 (32) | 1092 (68) | 43 (33, 51)† |
| Single vaccination | 83 (26) | 241 (74) | 362 (25) | 1092 (75) | 20 (-16, 45)† |
| Unvaccinated | Reference | ||||
| H3N2 | |||||
| Two-dose vaccination | 31 (32) | 66 (68) | 522 (32) | 1092 (68) | 42 (-9, 69)† |
| Single vaccination | 25 (27) | 66 (73) | 362 (22) | 1092 (75) | −2 (-24, 16)† |
| Unvaccinated | Reference | ||||
| H1N1p | |||||
| Two-dose vaccination | 39 (26) | 113 (74) | 522 (32) | 1092 (68) | 48 (31, 60)† |
| Single vaccination | 35 (24) | 113 (76) | 362 (22) | 1092 (75) | 35 (-30, 67)† |
| Unvaccinated | Reference | ||||
| B | |||||
| Two-dose vaccination | 16 (24) | 50 (76) | 522 (32) | 1092 (68) | 36 (-34, 69)† |
| Single vaccination | 20 (29) | 50 (71) | 362 (22) | 1092 (75) | 3 (-110, 55)† |
| Unvaccinated | Reference | ||||
†
Adjusted for sex, age (in months), month of illness onset, pre-existing conditions, year and country. Random effect model with a robust variance adjusted for cluster samples (country) by the Huber-White method.