This web page provides estimates on the burden of influenza (flu) and the effects of annual flu vaccination in the United States for the 2023–2024 season.
For more than a decade, CDC has used a model to estimate the annual number of flu illnesses, medical visits, hospitalizations, and deaths during the flu season, and to estimate the impact that flu vaccination had on illness outcomes in the United States123456. The methods used to calculate the estimates of flu burden prevented by flu vaccination have been described previously16. CDC uses the estimates of the impact of flu vaccination to inform policy and communications promoting vaccination as the best way to prevent flu.
CDC estimates that during the 2023-2024 season, flu vaccination prevented flu-related illnesses, medical visits, hospitalizations, and deaths.
| Symptomatic Illnesses | Medical Visits | Hospitalizations | Deaths | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Age group | Vaccine Coverage (%) | Adjusted VE (95 % CI) | Inpatient Adjusted VE (95 % CI) | Estimate | 95 % UI | Estimate | 95 % UI | Estimate | 95 % UI | Estimate | 95 % UI | |
| 6 months-4 years | 63,5 % | 65 % (64.7, 65.3) | 71,8 % (71.3, 72.2) | 1 422 807 | (1,084,091, 2,429,071) | 953 281 | (722,949, 1,630,197) | 11 663 | (8,843, 19,942) | 173 | (37, 482) | |
| 5-17 years | 52,6 % | 52 % (51.8, 52.2) | 51 % (50.7, 51.4) | 3 098 105 | (2,306,816, 7,218,811) | 1 611 014 | (1,187,172, 3,793,928) | 8 283 | (6,171, 19,309) | 93 | (25, 415) | |
| 18-49 years | 32,4 % | 51,4 % (51.1, 51.6) | 51,8 % (51.5, 52) | 2 729 736 | (1,843,164, 7,126,831) | 1 010 002 | (672,347, 2,650,698) | 15 463 | (10,441, 40,391) | 513 | (142, 1,784) | |
| 50-64 years | 45,9 % | 40,9 % (40.5, 41.2) | 42,3 % (42.1, 42.6) | 1 757 607 | (1,237,781, 4,206,912) | 755 771 | (527,270, 1,817,548) | 19 447 | (13,693, 46,531) | 1 311 | (358, 3,795) | |
| 65+ years | 69,1 % | 37,4 % (37.1, 37.7) | 34,5 % (34.3, 34.7) | 779 211 | (524,520, 1,930,185) | 436 358 | (291,321, 1,081,948) | 63 930 | (43,084, 158,152) | 5 815 | (2,259, 41,310) | |
| All ages | 49,9 % (49.7, 50) | 40,1 % (40, 40.2) | 9 787 466 | (8,133,904, 16,881,781) | 4 766 427 | (3,980,513, 8,094,186) | 118 786 | (94,989, 223,408) | 7 905 | (4,003, 43,636) | ||
Additional information about How CDC Estimates the Burden of Flu Prevented by Vaccination and the 2023-2024 Burden Prevented by Vaccination can be found in the 2023-2024 Influenza Activity report.
