Global Influenza Programme
We provide Member States with strategic guidance, technical support and coordination of activities essential to make their health systems better prepared against seasonal, zoonotic and pandemic influenza threats to populations and individuals.
Candidate vaccine viruses and potency testing reagents
Northern hemisphere influenza seasons
2025-2026
Southern hemisphere influenza seasons
2025
Previous seasons
2024-2025
2023-2024
2024
2023
2022-2023
2022
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 190 KB | Download | |
| 2. A(H1N1)pdm09 - Cell culture-derived | 162 KB | Download | |
| 3. A(H3N2) - Egg-derived | 171 KB | Download | |
| 4. A(H3N2) - Cell culture-derived | 185 KB | Download | |
| 5. Influenza B Yamagata Lineage - Egg-derived | 195 KB | Download | |
| 6. Influenza B Yamagata Lineage - Cell culture-derived | 191 KB | Download | |
| 7. Influenza B Victoria Lineage - Egg-derived | 169 KB | Download | |
| 8. Influenza B Victoria Lineage - Cell culture-derived | 188 KB | Download |
2021-2022
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 177 KB | Download | |
| 2. A(H1N1)pdm09 - Cell culture-derived | 157 KB | Download | |
| 3. A(H3N2) - Egg-derived | 166 KB | Download | |
| 4. A(H3N2) - Cell culture-derived | 181 KB | Download | |
| 5. Influenza B Yamagata Lineage - Egg-derived | 240 KB | Download | |
| 6. Influenza B Yamagata Lineage - Cell culture-derived | 139 KB | Download | |
| 7. Influenza B Victoria Lineage - Egg-derived | 144 KB | Download | |
| 8. Influenza B Victoria Lineage - Cell cultured-derived | 161 KB | Download |
2021
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 183 KB | Download | |
| 2. A(H1N1)pdm09 - Cell culture-derived | 176 KB | Download | |
| 3. A(H3N2) - Egg-derived | 212 KB | Download | |
| 4. A(H3N2) - Cell culture-derived | 154 KB | Download | |
| 5. Influenza B Yamagata Lineage - Egg-derived | 196 KB | Download | |
| 6. Influenza B Yamagata Lineage - Cell culture-derived | 153 KB | Download | |
| 7. Influenza B Victoria Lineage - Egg-derived | 173 KB | Download | |
| 8. Influenza B Victoria Lineage - Cell culture-derived | 164 KB | Download |
2020-2021
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 230 KB | Download | |
| 2. A(H1N1)pdm09 - Cell culture-derived | 548 KB | Download | |
| 3. A(H3N2) - Egg-derived | 227 KB | Download | |
| 4. A(H3N2) - Cell culture-derived | 393 KB | Download | |
| 5. Influenza B Yamagata Lineage - Egg-derived | 238 KB | Download | |
| 6. Influenza B Yamagata Lineage - Cell culture-derived | 393 KB | Download | |
| 7. Influenza B Victoria Lineage - Egg-derived | 266 KB | Download | |
| 8. Influenza B Victoria Lineage - Cell culture-derived | 385 KB | Download |
2020
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 217 KB | Download | |
| 2. A(H1N1)pdm09 - Cell culture-derived | 171 KB | Download | |
| 3. A(H3N2) - Egg-derived | 212 KB | Download | |
| 4. A(H3N2) - Cell culture-derived | 154 KB | Download | |
| 5. Influenza B Yamagata Lineage - Egg-derived | 230 KB | Download | |
| 6. Influenza B Yamagata Lineage - Cell culture-derived | 153 KB | Download | |
| 7. Influenza B Victoria Lineage - Egg-derived | 219 KB | Download | |
| 8. Influenza B Victoria Lineage - Cell culture-derived | 164 KB | Download |
2019-2020
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 608 KB | Download | |
| 2. A(H1N1)pdm09 - Cell culture-derived | 147 KB | Download | |
| 3. A(H3N2) - Egg-derived | 633 KB | Download | |
| 4. A(H3N2) - Cell culture-derived | 390 KB | Download | |
| 5. Influenza B Yamagata Lineage - Egg-derived | 615 KB | Download | |
| 6. Influenza B Yamagata Lineage - Cell culture-derived | 151 KB | Download | |
| 7. Influenza B Victoria Lineage - Egg-derived | 145 KB | Download | |
| 8. Influenza B Victoria Lineage - Cell culture-derived | 149 KB | Download |
2019
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 238 KB | Download | |
| 2. A(H1N1)pdm09 - Cell culture-derived | 224 KB | Download | |
| 3. A(H3N2) - Egg-derived | 196 KB | Download | |
| 4. A(H3N2) - Cell culture-derived | 128 KB | Download | |
| 5. Influenza B Yamagata Lineage - Egg-derived | 190 KB | Download | |
| 6. Influenza B Yamagata Lineage - Cell culture-derived | 151 KB | Download | |
| 7. Influenza B Victoria Lineage - Egg-derived | 642 KB | Download | |
| 8. Influenza B Victoria Lineage - Cell culture-derived | 189 KB | Download |
2018-2019
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 126 KB | Download | |
| 2. A(H3N2) - Egg-derived | 96 KB | Download | |
| 3. A(H3N2) - Cell culture-derived | 118 KB | Download | |
| 4. Influenza B Victoria Lineage - Egg-derived | 131 KB | Download | |
| 5. Influenza B Victoria Lineage - Cell culture-derived | 161 KB | Download | |
| 6. Influenza B Yamagata Lineage - Egg-derived | 139 KB | Download | |
| 7. Influenza B Yamagata Lineage - Cell culture-derived | 118 KB | Download |
2018
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 127 KB | Download | |
| 2. A(H3N2) - Egg-derived | 150 KB | Download | |
| 3. A(H3N2) - Cell culture-derived | 96 KB | Download | |
| 4. Influenza B Yamagata Lineage - Egg-derived | 139 KB | Download | |
| 5. Influenza B Yamagata Lineage - Cell culture-derived | 114 KB | Download | |
| 6. Influenza B Victoria Lineage - Egg-derived | 156 KB | Download | |
| 7. Influenza B Victoria Lineage - Cell culture-derived | 112 KB | Download |
2017-2018
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 144 KB | Download | |
| 2. A(H3N2) - Egg-derived | 403 KB | Download | |
| 3. A(H3N2) - Cell culture-derived | 117 KB | Download | |
| 4. Influenza B Yamagata Lineage - Egg-derived | 143 KB | Download | |
| 5. Influenza B Yamagata Lineage - Cell culture-derived | 116 KB | Download | |
| 6. Influenza B Victoria Lineage - Egg-derived | 144 KB | Download | |
| 7. Influenza B Victoria Lineage - Cell culture-derived | 117 KB | Download |
2017
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 150 KB | Download | |
| 2. A(H3N2) - Egg-derived | 120 KB | Download | |
| 3. A(H3N2) - Cell culture-derived | 134 KB | Download | |
| 4. Influenza B Yamagata Lineage - Egg-derived | 146 KB | Download | |
| 5. Influenza B Yamagata Lineage - Cell culture-derived | 157 KB | Download | |
| 6. Influenza B Victoria Lineage - Egg-derived | 127 KB | Download | |
| 7. Influenza B Victoria Lineage - Cell culture-derived | 116 KB | Download |
2016-2017
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 169 KB | Download | |
| 2. A(H3N2) - Egg-derived | 143 KB | Download | |
| 3. Influenza B Yamagata Lineage - Egg-derived | 135 KB | Download | |
| 4. Influenza B Victoria Lineage - Egg-derived | 124 KB | Download |
2016
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 159 KB | Download | |
| 2. A(H3N2) - Egg-derived | 145 KB | Download | |
| 3. A(H3N2) - Cell culture-derived | 138 KB | Download | |
| 4. Influenza B Yamagata Lineage - Egg-derived | 140 KB | Download | |
| 5. Influenza B Yamagata Lineage - Cell culture-derived | 308 KB | Download | |
| 6. Influenza B Victoria Lineage - Egg-derived | 146 KB | Download | |
| 7. Influenza B Victoria Lineage - Cell culture-derived | 310 KB | Download |
2015-2016
| Title | Type | Size | |
| 1. A(H1N1)pdm09 - Egg-derived | 164 KB | Download | |
| 2. A(H3N2) - Egg-derived | 153 KB | Download | |
| 3. Influenza B Yamagata Lineage - Egg-derived | 146 KB | Download | |
| 4. Influenza B Victoria Lineage - Egg-derived | 154 KB | Download |
2015
| Title | Type | Size | |
| 1. A(H1N1)pdm09 – Egg-derived | 179 KB | Download | |
| 2. A(H3N2) – Egg-derived | 109 KB | Download | |
| 3. Influenza B Yamagata Lineage – Egg-derived | 196 KB | Download | |
| 4. Influenza B Victoria Lineage – Egg-derived | 224 KB | Download |
2014-2015
| Title | Type | Size | |
| 1. A(H1N1)pdm09 – Egg-derived | 167 KB | Download | |
| 2. A(H3N2) - Egg-derived | 153 KB | Download | |
| 3. Influenza B Victoria Lineage – Egg-derived | 175 KB | Download | |
| 4. Influenza B Yamagata Lineage – Egg-derived | 152 KB | Download |
2014
| Title | Type | Size | |
| 1. A(H1N1)pdm09 – Egg-derived | 168 KB | Download | |
| 2. A(H3N2) – Egg-derived | 151 KB | Download | |
| 3. Influenza B Yamagata Lineage – Egg-derived | 139 KB | Download | |
| 4. Influenza B Victoria Lineage – Egg-derived | 157 KB | Download |
2013-2014
| Title | Type | Size | |
| 1. A(H1N1)pdm09 – Egg-derived | 118 KB | Download | |
| 2. A(H3N2) – Egg-derived | 148 KB | Download | |
| 3. Influenza B Victoria Lineage | 112 KB | Download | |
| 4. Influenza B Yamagata Lineage | 152 KB | Download | |
| 5. Influenza B Lineage | 154 KB | Download |
2013
| Title | Type | Size | |
| 1. A(H1N1)pdm09 | 119 KB | Download | |
| 2. A(H3N2) | 164 KB | Download | |
| 3. Influenza B Yamagata Lineage | 148 KB | Download | |
| 4. Influenza B Victoria Lineage | 136 KB | Download |
2012-2013
| Title | Type | Size | |
| 1. A(H1N1)pdm09 | 172 KB | Download | |
| 2. A(H3N2) - Perth | 122 KB | Download | |
| 3. A(H3N2) - Victoria | 127 KB | Download | |
| 4. Influenza B | 165 KB | Download |
2012
| Title | Type | Size | |
| 1. A(H3N2) - Victoria | 128 KB | Download |
2011-2012
| Title | Type | Size | |
| 1. A(H1N1)pdm09 | 171 KB | Download | |
| 2. Influenza B | 145 KB | Download |
2011
| Title | Type | Size | |
| 1. A(H1N1)pdm09 | 144 KB | Download | |
| 2. A(H3N2) - A/Perth/16/2009(H3N2)-like | 142 KB | Download |
2010-2011
| Title | Type | Size | |
| 1. A(H1N1)pdm09 | 106 KB | Download | |
| 2. A(H3N2) – Perth1 | 124 KB | Download | |
| 3. Influenza B | 119 KB | Download |
2010
| Title | Type | Size | |
| 1. Influenza B | 89 KB | Download |