I’ve heard of studies comparing unvaccinated to vaccinated populations, and the vaccinated populations have more issues. Is this true?

The studies that compare vaccinated to unvaccinated populations give conflicting results, and the answer depends heavily on which study you read and how well it accounts for the fact that healthier people tend to get vaccinated.

The strongest evidence for a benefit comes from a Norwegian study of 4.6 million adults. It found that people who received three or more mRNA doses had a much lower risk of dying from any cause than unvaccinated people, with about a 60% lower rate across all age groups [1]. The study adjusted for sex, location, and medical risk, but the authors acknowledge that unmeasured factors like low income could still skew the result [1]. A Hungarian study of 6.4 million adults also found lower all-cause death among vaccinated people after trying to correct for the "healthy vaccinee" effect [5].

But other studies tell a different story. An analysis of UK data from April 2021 to May 2023 found that the initial mortality advantage in vaccinated people faded over time. By the end of the period, vaccinated people had higher rates of non-COVID death than unvaccinated people [2][4]. The authors of that study interpret this as possible long-term harm from vaccination [4]. A US county-level study of over 3,000 counties found that higher vaccination rates were linked to more excess deaths in 2022 and 2023 [3]. A European study of 31 countries found the same pattern: higher vaccination uptake in 2021 predicted higher excess mortality in 2022 [6].

The problem is that observational studies comparing vaccinated to unvaccinated people are easily fooled by the "healthy vaccinee effect." People who choose to get vaccinated tend to be healthier, wealthier, and more health-conscious to begin with. That makes them look better in the data even if the vaccine does nothing. The studies that find harm may be capturing the opposite: people who refuse vaccination may be different in ways that protect them, or the unvaccinated group may get depleted of its sickest members over time.

My call: the evidence is genuinely mixed and no single study settles it. The studies that show benefit are large and well-done but cannot fully eliminate the healthy-user bias. The studies that show harm are also large but ecological, meaning they compare groups rather than individuals. The honest answer is that the question is not settled, and the absence of a large, long-term randomized trial means we are guessing.

Confidence: low. The evidence is contradictory and the study designs are too weak to resolve the contradiction.