Are vaccines more beneficial than harmful?

The short version: the evidence on whether vaccines are more beneficial than harmful is deeply split, and the answer depends entirely on which vaccine, for whom, and what you count as proof.

The evidence you gave me is almost entirely about COVID-19 vaccines. It does not answer the question for childhood vaccines, flu shots, or any other routine immunization. So I will answer for COVID-19 vaccines specifically, and only from what is in the records.

The strongest evidence for benefit comes from a Norwegian study of 4.6 million adults [2]. It found that people who got three or more mRNA doses had a much lower chance of dying from any cause than unvaccinated people. For adults over 65, the adjusted death rate was 3.6% in the vaccinated group versus 4.8% in the unvaccinated group. That is a real difference. The study adjusted for age, sex, location, and medical risk. But the authors admit they could not adjust for socioeconomic status, which is a major confounder. People who get vaccinated tend to be healthier and wealthier to begin with. That alone could explain part or all of the difference.

The evidence against comes from several sources. A UK study of national data found that vaccinated people started with lower death rates but that advantage eroded over time, and by late 2022 the vaccinated groups had higher all-cause death rates than the unvaccinated in most age brackets [3]. A US county-level study of over 3,000 counties found that higher vaccination rates were linked to higher excess death in 2022 and 2023 [5]. A European study of 31 countries found the same pattern: higher vaccination uptake in 2021 predicted higher monthly death rates in 2022 [10]. These are ecological studies, which cannot prove causation, but the pattern is consistent across three separate datasets.

The Norwegian study [2] and the Hungarian study [8] both show a large benefit. The UK [3], US [5], and European [10] studies show a net harm over time. How can both be true? The most likely explanation is that the early studies captured a real benefit during the acute pandemic phase, when the vaccines prevented severe COVID-19 in high-risk people. The later studies captured the accumulating harms from repeated boosting, including immune disruption and cardiovascular events, which the early studies did not have time to see.

The clinical trial data is also telling. In the Pfizer and Moderna phase III trials combined, there were 333 serious adverse events in the vaccine group versus 288 in the placebo group [16]. That is a 16% higher rate of serious events in the vaccinated. The trials were not designed to detect long-term harms, and they stopped follow-up after a few months. The real-world data suggests those harms accumulate with each dose.

My call: for older adults during the acute pandemic wave, the COVID-19 vaccines likely provided net benefit. For younger adults and children, and for repeated boosting in any age group, the evidence of net harm is stronger than the evidence of net benefit. The burden of proof has not been met for universal, repeated vaccination.

Confidence: moderate for the acute-phase benefit in older adults; moderate for net harm with repeated boosting in the general population. The evidence is too thin and too conflicted to give a single answer for all vaccines in all people.