Could body temperature be used as surrogate measure of mRNA-based vaccination efficacy in the general population?

Predicting the humoral, cellular and clinical response to coronavirus disease 2019 (COVID-19) vaccination remains a central aspect for efficiently tackling the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Several current studies have focused on predicting the clinical response to COVID-19 vaccination by testing both immunological and cellular biomarkers. Nonetheless, this strategy is plagued by a number of drawbacks, so that a “biological marker” which may help predicting vaccine efficacy, efficiently surrogating laboratory-based tests, would be a valuable resource for optimizing vaccine delivery. A number of recent studies, summarized in this clinical practice review, have repeatedly emphasized the existence of a significant relationship between increased body temperature and humoral response after mRNA-based COVID-19 vaccination. Therefore, we put forward the idea that fever should be no longer considered only an adverse (almost undesirable) post-vaccination side effect, wherein its onset may actually reflect enhanced immunological response to vaccine, and its measurement could hence be used for screening at least mRNA-based vaccine immunogenicity in terms of humoral response up to 3 months after mRNA-based COVID-19 vaccination by using specifically validated algorithms incorporating the integrate assessment of body temperature and anti-SARS-CoV-2 antibodies.