In experimental conditions, it has been demonstrated that vaccine efficacy and the toxicity is depending on cytokine-induced immunoinflammatory response, and that they may be modulate through a neuroimmune approach, which neuroendocrine agents, such as the pineal hormone melatonin (MLT) and the enzymatic product of ACE2, the angiotensin 1-7 (Ang 1-7). On these bases, a preliminary study was planned to evaluate the influence of an oral peri-vaccination regimen with MLT plus Ang 1-7 on the subjective safety of Covid19 Pfizer-BioNTech (PF) and AstraZeneca (AZ) vaccines.

The study included 60 subjects, 30 of whom received PF vaccine, while the other 30 subjects were treated by AZ vaccine. Both groups of subjects were randomized to receive the only vaccine or vaccine plus Ang 1-7 (0.5 mg/day in the morning) and MLT (10 mg/day in the evening) regimen, starting 3 days prior to vaccine and for the successive 4 days. The percentage of episodes of fever higher than 38°C, asthenia and myalgia were significantly reduced by the concomitant administration of Ang 1-7 plus MLT.

This preliminary study shows the possibility to modulate the safety of Covid19 vaccine through a neuroimmune approach consisting of Ang 1-7 plus MLT. Further studies will be required to confirm these data, and to evaluate the impact not only on the safety, but also on the efficacy of Covid19 vaccination.