Beyond correlation and causation: epistemic caution, anomalous findings, and COVID-19 vaccine safety

Abstract The COVID-19 pandemic exposed science’s adaptive strengths and epistemic limits. In fact, in the pandemic, mRNA vaccines are attributed to have saved millions of lives. The maxim “correlation does not imply causation” is an essential safeguard against premature causal inference. However, its use may become epistemically restrictive when the absence of established causality is treated as sufficient reason not to investigate (severe) vaccine adverse events. This article examines the conditions under which a valid cautionary principle may have contributed to premature epistemic closure. Thomas Kuhn’s theory of scientific paradigms is used as one interpretative lens rather than as an empirical explanation of institutional behaviour. We argue that the correlation–causation distinction can shift from a heuristic of caution to an instrument of epistemic conservatism, reinforcing prevailing frameworks and discouraging exploration of anomalies. A published autopsy case report involving multifocal necrotizing encephalitis and myocarditis after BNT162b2 vaccination is examined as an illustrative and hypothesis-generating case, not as representative evidence of systematic institutional conduct. A qualitative approach using Bradford Hill’s criteria provides partial, inconclusive evidence of a causal relationship while also exposing the methodological limits of the tool employed. The results of the analysis showed that one of the nine criteria demonstrated support of causality, seven were partially supported, and one did not support causality. The analysis suggests, but does not prove, a causal relationship between the BNT162b2 vaccine and multifocal necrotizing encephalitis. The absence of the nucleocapsid protein does not provide definitive evidence to demonstrate a vaccine origin. Analytical methods are described which can distinguish between the wild-type SARS-CoV-2 spike protein and the recombinant spike protein expressed following mRNA vaccination. The absence of evidence does not mean evidence of absence and we must keep an open mind to this when reviewing such evidence on causality.