A recent study reported that the high-dose quadrivalent influenza vaccine provided superior immunogenicity and efficacy versus the standard-dose quadrivalent vaccine in the elderly. However, we need to view these results in terms of public health benefits as well. The Number Needed to Vaccinate (NNV) is an important tool to measure the benefit of a given vaccine. Further, NNV evaluates the benefits of a vaccine in preventing and controlling communicable diseases. Considering the target of vaccination and coverage of 75% not met in the elderly in Europe, it is important not to prioritize one vaccine over the other, but rather to increase the vaccine coverage with all the available vaccines.
Keywords: Number needed to vaccinate; at-risk group prioritization; flu; high-dose quadrivalent vaccine; influenza vaccine; standard-dose quadrivalent vaccine; vaccine coverage; vaccine shortage.