Is the High-Dose Flu Vaccine Better Than the Standard Dose for Preventing Severe Outcomes?

High-dose influenza vaccine reduces the incidence of laboratory-confirmed influenza in older adults by about 25% relative to standard-dose vaccine, but does it also reduce hospitalizations? To find out, investigators launched two nearly identical, industry-sponsored, pragmatic randomized controlled trials in Denmark and Spain, with the primary endpoint being hospitalization for either influenza or pneumonia. The studies took place during the past 2 to 3 influenza seasons, with about 330,000 older adults in the Danish study and 130,000 in the Spanish study (mean age in both studies, ≈73 years).