biostudies-literatureLutz CSU.S. Department of EnergyOak Ridge Institute for Science and EducationCenters for Disease Control and PreventionIntramural CDC HHS4219-4230https://www.ebi.ac.uk/biostudies/studies/S-EPMC12288909biostudies-literatureUnknown39(30)<h4>Background</h4>During the 2009 influenza A(H1N1)pdm09 pandemic, 77 countries received donated monovalent A(H1N1)pdm09 vaccine through the WHO Pandemic Influenza A(H1N1) Vaccine Deployment Initiative. However, 47% did not receive their first shipment until after the first wave of virus circulation, and 8% did not receive their first shipment until after the WHO declared the end of the pandemic. Arguably, these shipments were too late into the pandemic to have a substantial effect on virus transmission or disease burden during the first waves of the pandemic.<h4>Objectives</h4>In order to evaluate the potential benefits of earlier vaccine availability, we estimated the number of illnesses and deaths that could be averted during a 2009-like influenza pandemic under five different vaccine-VaccineEstimating the number of averted illnesses and deaths as a result of vaccination against an influenza pandemic in nine low- and middle-income countries.PMC12288909CC999999Bresee JSLafond KEAzziz-Baumgartner EBiggerstaff MReed CLutz CSPorter RMRolfes MAfalseEstimating the number of averted illnesses and deaths as a result of vaccination against an influenza pandemic in nine low- and middle-income countries.<h4>Background</h4>During the 2009 influenza A(H1N1)pdm09 pandemic, 77 countries received donated monovalent A(H1N1)pdm09 vaccine through the WHO Pandemic Influenza A(H1N1) Vaccine Deployment Initiative. However, 47% did not receive their first shipment until after the first wave of virus circulation, and 8% did not receive their first shipment until after the WHO declared the end of the pandemic. Arguably, these shipments were too late into the pandemic to have a substantial effect on virus transmission or disease burden during the first waves of the pandemic.<h4>Objectives</h4>In order to evaluate the potential benefits of earlier vaccine availability, we estimated the number of illnesses and deaths that could be averted during a 2009-like influenza pandemic under five different vaccine-2021-01-01T00:00:00Z2021 Jul2026-03-31T10:48:30.431Z2025-08-28T03:05:46.633ZS-EPMC122889093411934810.1016/j.vaccine.2021.05.006