Anti‐SARS‐CoV‐2 mRNA vaccines, their efficiency, side effects and controversies

Abstract

Dear Editor, I recently read the letter to your journal: 'Role of the antigen presentation process in the immunization mechanism of the genetic vaccines against COVID-19 and the need for biodistribution evaluations' by P. Polykretis. 1 The author suggests that anti-SARS-CoV-2 mRNA vaccines may cause SARS-CoV-2 spike protein expression not only in regional lymph nodes but also in many organs including spleen, liver, pituitary gland, thyroid, ovaries and in other tissues. Polykretis further suggests that this expression may induce autoimmune disease and as such lead to dangerous and harmful side effects.The statement that the biodistribution and expression of the spike protein is significant in many different tissues is, however, contradicted even by specific references cited in the letter itself. As an example, it is stated in references 6 and 7 that in experimental rats, lipid nanoparticles, containing mRNA vaccine, were distributed mainly to the liver, which plays a role in detoxification of organism and is therefore necessary to neutralize the drugs. If any pathogenic effects were visible in liver, they were mild, transient and reversible, and no autoimmunity was observed in this organ. Other organs and tissues were not endangered. Furthermore, reference 9 refers to a large panel of publications describing single cases of severe adverse effects of mRNA vaccination, out of thousands healthy vaccinees, and reference 10 is not a peer-reviewed article, but an internet site with links to 'FDA documents' that is impossible to open, at least for this author. Reports on adverse events show that they are rare and transient 2,3 (see below).SARS-CoV-2 infection and COVID-19 may pose higher risk of autoimmune diseases 4-6 than mRNA vaccination. Severe COVID-19 may be associated with autoimmune phenomena in predisposed patients, although these may be only epiphenomena. 4 Indeed, different neurological symptoms were observed in postacute COVID-19 patients, including Guillan-Barre syndrome. 5 Among anti-COVID-vaccinated patients, Guillan-Barre syndrome had increased frequency in Ad26.COV2.S vaccine but not in mRNA vaccines BNT162b2 and mRNA-1273 groups. 6 Therefore, although COVID-19 may bring signs