Ferdinands et al.: 'Waning Vaccine Effectiveness Against Influenza-Associated Hospitalizations Among Adults, 2015–2016 to 2018–2019, US Hospitalized Adult Influenza Vaccine Effectiveness Network'
by Paul Alexander
Maximum vaccine effectiveness (VE) was observed shortly after vaccination, followed by an absolute decline in VE of about 8%–9% per month postvaccination.
SOURCE:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8499703/pdf/ciab045.pdf