Letter to the Editor
Volume 2 | Issue 1
Melatonin as an Adjuvant in COVID-19 Vaccination
1MARGen Clinic, Camino de Ronda, Granada, Spain
2Department of Cell Systems and Anatomy, UT Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
*Corresponding author: Jan Tesarik, MD, PhD, MARGen Clinic, Camino de Ronda 2, 18006 Granada, Spain, Tel: +34-606376992, E-mail: firstname.lastname@example.org
Citation: Tesarik J, Reiter RJ (2021) Melatonin as an Adjuvant in COVID-19 Vaccination. J SARS-CoV-2 COVID 2:009.
Copyright © Tesarik J, et al.
The development of COVID-19 vaccines represents a new hope to stabilize and reduce the progression of the pandemic. However, their use may not be free of serious side-effects, especially allergic reactions including anaphylaxis. This complication was observed after the first dose of both Moderna  and Pfizer-BioNTech  COVID-19 vaccines. Despite the relatively low incidence of these complications, they have to be taken seriously into account.
In addition, an unexpected rise in reported COVID-19 cases due to the emergence of new SARS-CoV-2 variants, observed since December 2020, raises an issue of whether the existing COVID-19 vaccines will be able to protect against new SARS-CoV-19 variants, both those already existing  and those which may appear in the future.
Melatonin, an endogenously-produced molecule, inhibits different forms of allergic reactions, including atopic dermatitis, atopic rhinitis and asthma, and prevents the vicious circle of pro-inflammatory cytokine activation, known as the "cytokine storm" . These protective actions are due to a unique combination of immunomodulatory, anti-oxidative, and anti-inflammatory activities of this multifaceted molecule .
Adhering to the "First do no harm" principle, it has to be stressed that melatonin treatment has a large safety margin without serious adverse effects . If administered together with a COVID-19 vaccine, it would be likely to reduce the unpredictable risk of serious allergic reactions, without any risk of additional health damage. Moreover, according to a recent analysis, melatonin is likely to act directly against the virus SARS-CoV-2 itself, by attenuating growth factor receptor signalling required for the virus replication in the infected cells . These four antiviral actions of melatonin are not strictly strain-specific, and melatonin can act against a large range of viruses causing respiratory tract infections . Accordingly, melatonin is highly likely to be effective against different variants resulting from SARS-CoV-2 mutations, both those already existing and those potentially appearing in the future.
Taken together, melatonin may not only protect individuals receiving COVID-19 vaccines against allergic reactions, but is is also likely to potentiate the vaccines' antiviral action. This is important because none of the existing vaccines has 100% efficacy. Moreover, in the event of possible future mutations of SARS-CoV-2, which may render the resulting variants less sensitive to the existing vaccines, melatonin can be used to cover the time period between the appearance of a vaccine-resistant virus variant and the development of a new vaccine adapted to this new condition.
Declaration of Interests
No potential conflict of interest relevant to this letter was reported.
- CDC COVID-19 Response Team; Food and Drug Administration. Allergic reactions including anaphylaxis after receipt of the first dose of Moderna COVID-19 vaccine - United States. MMWR Morb Mortal Wkly Rep 70: 125-129.
- Shimabukuro T, Nair N (2021) Allergic reactions including anaphylaxis after receipt of the first dose of Pfizer-BioNTech COVID-19 vaccine. JAMA 325: 780-781.
- Fontanet A, Autran B, Lina B, et al. (2021) SARS-CoV-2 variants and ending the COVID-19 pandemic. Lancet 397: 952-954.
- Anderson G, Reiter RJ (2020) Melatonin: Roles in influenza, Covid-19, and other viral infections. Rev Med Virol 30: e2109.
- Tesarik J (2020) Melatonin attenuates growth factor receptor signaling required for SARS-CoV-2 replication. Melatonin Res 3: 534-537.