Inclusion Criteria:  Be ≥ 18 years old. Indistinct sex. Having given their informed consent. No respiratory problems during the last 21 days prior to administration of the single dose. No conditions or alterations in the physical examination, laboratory values and cabinet that in the opinion of the investigator may interfere with the participation of the subject in the study or require a more detailed medical study. Negative PCR test for SARS-CoV-2 during the screening visit. Negative pregnancy test in women with pregnancy potential. Signature of commitment for the use of highly effective contraceptive methods for at least 30 days after administration of the intramuscular injection or intranasal. In case of presenting any chronic disease with medical management, it must be controlled and stable without changes in treatment during the last three months prior to the scrutiny visit. Commitment to maintain adequate prevention measures to avoid the contagion by SARS-CoV-2 during their participation in the study, considering themselves these strict use during the first 14 days after the baseline visit (Use of face masks in closed places, social distancing measures in spaces open, and frequent hand washing). Present detectable titers of anti-Spike IgG in peripheral serum during the visit of screening with titers less than 1,200 U/mL in a chemiluminescence test. Submit proof of vaccination 4 months or more after the last vaccination  Have been vaccinated with the complete program of any of the following vaccines against SARS-CoV-2:  ModeRNA Pfizer AstraZeneca CanSino Sinovac Sinopharm Johnson & Johnson (Janssen) Sputnik V  Exclusion Criteria:  History of hypersensitivity or allergy to any of the components of the vaccine. History of severe anaphylactic reactions from any cause. History of seizures. Uncontrolled chronic diseases. Chronic diseases that require management with immunosuppressive agents or immune response modulators (eg, systemic corticosteroids, cyclosporine, rituximab among others). Oncological disease. Active participation, or during the last 3 months in any other clinical study or research experimental intervention. Use within 30 days prior to screening evaluation of any drug or herbal supplement, or alternative medicine (for example, transfer factor, chlorine dioxide, etc.) aimed at treating or preventing complications or contagion by SARS-CoV-2, or any other condition. Febrile illness at the time of the screening visit. Have received any vaccine (experimental or approved) during the 60 days prior to the scrutiny visit. Having received a blood transfusion or blood components during the last 4 months prior to the scrutiny hearing. Have been a plasma donor during the last 4 months prior to the visit of scrutiny. Have undergone dialysis or hemodialysis procedures during the last year prior to the scrutiny visit. Work on poultry or gamecock farms. History of substance abuse problems that in the opinion of the investigator could interfere with the subject's ability to adequately comply with the protocol guidelines.