Are vaccines protecting against COVID and flu on UK worthwhile?

For most healthy UK adults, the evidence does not show that repeated COVID-19 and flu shots are worthwhile, but the picture is different for the elderly and clinically vulnerable.

The retrieved evidence on COVID-19 vaccination in the UK is a 2021 modelling study, not a clinical trial [1]. It estimated that vaccinating priority groups (the elderly and healthcare workers) reduced deaths by about 88% and hospital admissions by about 66% in the modelled scenario [1]. This is a mathematical projection, not a direct measure of real-world outcomes, and it reflects the early pandemic when the population had no prior immunity. A 2024 review found that for healthy children, the benefits of COVID-19 vaccination are "diminished by high prior infection and immunity" [2]. The same logic applies to most healthy adults who have already had COVID-19 or been vaccinated multiple times.

For flu vaccination, a Scottish study found that extending the vaccine to everyone over 65 was associated with a reduction of about 730 to 775 excess all-cause deaths per flu season in that age group [4]. This is a population-level correlation, not proof that any given individual will benefit, and the study could not adjust for vaccine uptake rates [4]. A separate study found that prior flu vaccination was linked to 15% lower odds of hospitalisation or death in people who later got COVID-19 [3].

The key question is whether the benefit outweighs the risk for you. For a healthy 30-year-old, the risk of serious COVID-19 or flu is very low. The evidence does not show a clear net benefit from repeated boosting for this group. For someone over 65 or with underlying health conditions, the evidence is stronger that vaccination reduces the chance of severe outcomes.

My call: for healthy adults under 65, the evidence does not support routine annual COVID-19 and flu vaccination as clearly worthwhile. For the elderly and those with chronic conditions, the evidence suggests a meaningful reduction in hospitalisation and death, but the data is observational and the long-term safety of repeated boosting is not established by these records. Confidence: moderate.