Intradermal Vaccination: A Potential Tool in the Battle Against the COVID-19 Pandemic?

Abstract

This narrative review is the final output of an initiative of the SIM (Italian Society of Mesotherapy). A narrative review of scientific literature on the efficacy of fractional intradermal vaccination in comparison with full doses has been conducted for the following pathogens: influenza virus, rabies virus, poliovirus (PV), hepatitis B virus (HBV), hepatitis A virus (HAV), diphtheria-tetanus-pertussis bacterias (DTP), human papillomavirus (HPV), Japanese encephalitis virus (JE), meningococcus, varicella zoster virus (VZV) and yellow fever virus. The findings suggest that the use of the intradermal route represents a valid strategy in terms of efficacy and efficiency for influenza, rabies and HBV vaccines. Some systematic reviews on influenza vaccines suggest the absence of a substantial difference between immunogenicity induced by a fractional ID dose of up to 20% and the IM dose in healthy adults, elderly, immunocompromised patients and children. Clinical studies of remaining vaccines against other pathogens (HAV, DTP bacterias, JE, meningococcal disease, VZV, and yellow fever virus) are scarce, but promising. In the context of a COVID-19 vaccine shortage, countries should investigate if a fractional dosing scheme may help to save doses and achieve herd immunity quickly. SIM urges the scientific community and health authorities to investigate the potentiality of fractionate intradermal administration in anti-COVID-19 vaccination.

A Call to Action by the Italian Mesotherapy Society on Scientific Research

“…Research could definitively establish the drug-sparing effect of the intradermal administration pathway with practical implications for the immunological field as well, by, for example, reducing the dose necessary to obtain immunization against COVID-19. 13 In addition, research could help us to refine delivery techniques and to choose combination therapies, frequency and number of sessions.…”

“…11 These results suggest that ID could be used to expand supplies of vaccine, although further studies are needed before this strategy can be recommended for routine use. 12,13 https://doi.org/10.2147/DDDT.S321215…”

“… 20 , 21 Among the various fields of application of mesotherapy, immune prophylaxis represents a crucial area. 13 In fact, it has been shown that skin can amplify the effects of an intradermally administered antigen: a smaller amount of substance can develop a better immune response. This dose-sparing effect could increase vaccine availability for worldwide immunization campaigns.…”

“…10 Finally, ID has been identified as a useful administration route in immune prophylaxis. [11][12][13] It should be noted, however, that in spite of its wide diffusion mesotherapy still presents many unresolved questions, such that further preclinical and clinical study is needed to define its role in clinical practice. 14 In this context, researchers must first identify priority areas in which the therapy is most useful so as to concentrate research toward development and standardisation of mesotherapy technique in clinical practice.…”

An Update on mRNA-Based Viral Vaccines

“…It remains questionable and to be determined whether the efficacy of intranasal vaccination will be reproducible in humans as observed in animal models. Additionally, intradermal vaccination would provide dose sparing effects, expanding the coverage under the situation of a COVID-19 vaccine shortage [ 148 ]. Future studies are needed on the intradermal or intranasal application of mRNA vaccines.…”