- History of anaphylactic shock of any kind. - History of COVID-19 infection. - Participant received or plans to receive live attenuated vaccines within 4 weeks before and after day 0, or other not live vaccines within 14 days before and after day 0. - Pregnancy or breast-feeding at screening or Day 0 (vaccination time-point) or willingness/intention to become pregnant during the study. - Participant has a clinically significant acute illness (this does not include minor self-limited illness such as mild diarrhoea) or fever (temperature ≥38º C (100.4ºF) at screening or within 48 hours prior to the planned vaccination (Day 0). - Participant had a surgery requiring hospitalization (defined as inpatient stay for > 24 hours) before vaccination and he/she has not received the hospital discharge at day 0, or has a surgery requiring hospitalization planned within 12 weeks after study vaccine administration. Minor surgical procedures not requiring hospitalization are accepted. - Participant has any active malignancy even if under treatment except for (at the discretion of the investigator): Non-melanoma adequately treated skin cancer without evidence of disease, or, adequately treated uterine cervical carcinoma in situ without evidence of disease, or, adequately treated anal carcinoma in situ without evidence of disease, or, localized prostate cancer. - Participant has ongoing severe and non-stable psychiatric condition likely to affect participation in the study (e.g., ongoing and non-stable severe depression, recent suicidal ideation, severe eating disorder, psychosis). - Participant has a problematic or risk use of substances including alcohol (except tobacco) that can compromise the study follow-up. Problematic or risk use of psychoactive substances is understood as the one that causes evident damage, whether it is dependence or any other physical, psychological, or social problem or that carries a high risk of suffering these damages. The negative consequences that consumption causes to third parties could be included. - Participant has a bleeding disorder (e.g., factor deficiency, platelet disorder), blood dyscrasia, or continuous use of anticoagulants or has any condition that in the opinion of the investigator contraindicates intramuscular injections or frequent phlebotomy. The use of ≤ 325mg of aspirin or ≤ 75mg of clopidogrel per day as prophylaxis is permitted but not combined. - Participant has abnormal function of the immune system as in autoimmune diseases, asplenia, recurrent infections or congenital/acquired immunodeficiency. Participants under immune-modifying treatment for any cause. Permitted: participants with stable clinical conditions (e.g., autoimmune thyroiditis, celiac disease, type 1- diabetes) and participants living with HIV with CD4 T cell count ≥ 400 cells/mm3 under stable antiretroviral treatment with a fully suppressed viral load ≥ 1 year are permitted [one or two non-consecutives blips (HIV viral load ≤ 500 viral copies)]. - Participants have clinically significant and unstable cardiovascular, respiratory, hepatic, neurological, gastrointestinal, renal, or any other medical disorder as judged by the investigator and defined as disease requiring hospitalization or addition of new treatments or major dose adjustments within 3 months before screening. - Chronic or recurrent administration (during at least 14 days) of systemic immunosuppressant medication (defined as given by oral or parenteral routes) within 12 weeks preceding the planned administration of study vaccine (Day 0). The use of an oral prednisone dose <10mg per day or equivalent, ocular, topical, inhaled and nasal corticoids are allowed. - Subject has received immunoglobulins and/or blood-derived products 12 weeks prior vaccination (Day 0) or expects to receive them during the study. Participant received any immunotherapy (monoclonal antibodies, plasma) aimed to prevent or treat COVID-19 within 90 days preceding the planned administration of study vaccine. Monoclonal antibodies for other indications are allowed. - Participation in any research involving an investigational product (drug, biologic, device) within 12 weeks prior to vaccination and during the study. Participant has donated ≥ 450ml of blood products within 12 weeks before screening. Participant has any medical condition and/or finding that in the investigator opinion might increase participant risks, interfere with the study or impair interpretation of study data. - Historia de choque anafiláctico de cualquier tipo - Historia de infección por COVID-19 - El participante ha recibido o planea recibir vacuna/s vivas atenuadas 4 semanas antes y después del día 0, u otras vacunas no vivas 14 días antes y después del día 0. - Embarazada o dando pecho a día 0, o esperar quedar embarazada durante el estudio. - El participante tiene una patología aguda clínicamente significativa o fiebre ( ≥38º C (100.4ºF)) en el screening o 48 horas antes del día 0. - El participante ha tenido una cirugía que ha requerido hospitalización antes de la vacunación y aún no ha recibido el alta médica a día 0, o tiene una cirugía planeada que requiera hospitalización en las 12 semanas posteriores a la administración de la vacuna. - El participante tiene algún episodio de malignidad aunque esté en tratamiento, excepto el cancer de piel no-melanómico, carcinoma cervical uterino, carcinoma anal, cancer de prostata localizado. - El participante tiene una patología psiquiátrica severa y no estable que puede afectar la participación en el estudio. - El participante tiene un uso arriesgado o problemático de sustancias incluyendo el alcohol que puede comprometer el seguimiento del estudio. - El participante tiene un desorden del sangrado, o tiene alguna condición que a criterio del investigador contraindica la inyección intramuscular. - El participante tiene una función anormal del sistema inmune, excepto condiciones estables, como el HIV controlado. - El participante tiene una condición cardiovascular, respiratoria, hepática, neurológica, gastrointestinal, renal, o algún otro desorden que no esté estable a juicio del investigador en los 3 meses anteriores al screening o día 0. - Administración recurrente o crónica de medicación inmunosupresora. - El sujeto ha recibido inmunoglobulinas y/o productos derivados de la sangre 12 semanas antes de la vacunación (día 0) o espera recibirlos durante en estudio. - El participante ha recibido algún tipo de inmunoterapia (anticuerpos monoclonales, plasma) para prevenir el COVID-19 en los últimos 90 días antes de día 0. Los anticuerpos monoclonales para otras indicaciones estan permitidos. - Participación en alguna investigación que involucre productos en investigación (medicamento, biológico, equipo) en las 12 semanas antes de la vacunación y durante el transcurso del estudio. - El participante ha donado ≥ 450ml de sangre o productos derivador 12 semanas antes del screening. - El participante tiene alguna condición médica, que a juicio del investigador puede incrementar los riesgos del participante, interferir en el estudio o perjudicar la interpretación de los datos del estudio.

- History of anaphylactic shock of any kind. - History of COVID-19 infection. - Participant received or plans to receive live attenuated vaccines within 4 weeks before and after day 0, or other not live vaccines within 14 days before and after day 0. - Pregnancy or breast-feeding at screening or Day 0 (vaccination time-point) or willingness/intention to become pregnant during the study. - Participant has a clinically significant acute illness (this does not include minor self-limited illness such as mild diarrhoea) or fever (temperature ≥38º C (100.4ºF) at screening or within 48 hours prior to the planned vaccination (Day 0). - Participant had a surgery requiring hospitalization (defined as inpatient stay for > 24 hours) before vaccination and he/she has not received the hospital discharge at day 0, or has a surgery requiring hospitalization planned within 12 weeks after study vaccine administration. Minor surgical procedures not requiring hospitalization are accepted. - Participant has any active malignancy even if under treatment except for (at the discretion of the investigator): Non-melanoma adequately treated skin cancer without evidence of disease, or, adequately treated uterine cervical carcinoma in situ without evidence of disease, or, adequately treated anal carcinoma in situ without evidence of disease, or, localized prostate cancer. - Participant has ongoing severe and non-stable psychiatric condition likely to affect participation in the study (e.g., ongoing and non-stable severe depression, recent suicidal ideation, severe eating disorder, psychosis). - Participant has a problematic or risk use of substances including alcohol (except tobacco) that can compromise the study follow-up. Problematic or risk use of psychoactive substances is understood as the one that causes evident damage, whether it is dependence or any other physical, psychological, or social problem or that carries a high risk of suffering these damages. The negative consequences that consumption causes to third parties could be included. - Participant has a bleeding disorder (e.g., factor deficiency, platelet disorder), blood dyscrasia, or continuous use of anticoagulants or has any condition that in the opinion of the investigator contraindicates intramuscular injections or frequent phlebotomy. The use of ≤ 325mg of aspirin or ≤ 75mg of clopidogrel per day as prophylaxis is permitted but not combined. - Participant has abnormal function of the immune system as in autoimmune diseases, asplenia, recurrent infections or congenital/acquired immunodeficiency. Participants under immune-modifying treatment for any cause. Permitted: participants with stable clinical conditions (e.g., autoimmune thyroiditis, celiac disease, type 1- diabetes) and participants living with HIV with CD4 T cell count ≥ 400 cells/mm3 under stable antiretroviral treatment with a fully suppressed viral load ≥ 1 year are permitted [one or two non-consecutives blips (HIV viral load ≤ 500 viral copies)]. - Participants have clinically significant and unstable cardiovascular, respiratory, hepatic, neurological, gastrointestinal, renal, or any other medical disorder as judged by the investigator and defined as disease requiring hospitalization or addition of new treatments or major dose adjustments within 3 months before screening. - Chronic or recurrent administration (during at least 14 days) of systemic immunosuppressant medication (defined as given by oral or parenteral routes) within 12 weeks preceding the planned administration of study vaccine (Day 0). The use of an oral prednisone dose <10mg per day or equivalent, ocular, topical, inhaled and nasal corticoids are allowed. - Subject has received immunoglobulins and/or blood-derived products 12 weeks prior vaccination (Day 0) or expects to receive them during the study. Participant received any immunotherapy (monoclonal antibodies, plasma) aimed to prevent or treat COVID-19 within 90 days preceding the planned administration of study vaccine. Monoclonal antibodies for other indications are allowed. - Participation in any research involving an investigational product (drug, biologic, device) within 12 weeks prior to vaccination and during the study. Participant has donated ≥ 450ml of blood products within 12 weeks before screening. Participant has any medical condition and/or finding that in the investigator opinion might increase participant risks, interfere with the study or impair interpretation of study data. - Historia de choque anafiláctico de cualquier tipo - Historia de infección por COVID-19 - El participante ha recibido o planea recibir vacuna/s vivas atenuadas 4 semanas antes y después del día 0, u otras vacunas no vivas 14 días antes y después del día 0. - Embarazada o dando pecho a día 0, o esperar quedar embarazada durante el estudio. - El participante tiene una patología aguda clínicamente significativa o fiebre ( ≥38º C (100.4ºF)) en el screening o 48 horas antes del día 0. - El participante ha tenido una cirugía que ha requerido hospitalización antes de la vacunación y aún no ha recibido el alta médica a día 0, o tiene una cirugía planeada que requiera hospitalización en las 12 semanas posteriores a la administración de la vacuna. - El participante tiene algún episodio de malignidad aunque esté en tratamiento, excepto el cancer de piel no-melanómico, carcinoma cervical uterino, carcinoma anal, cancer de prostata localizado. - El participante tiene una patología psiquiátrica severa y no estable que puede afectar la participación en el estudio. - El participante tiene un uso arriesgado o problemático de sustancias incluyendo el alcohol que puede comprometer el seguimiento del estudio. - El participante tiene un desorden del sangrado, o tiene alguna condición que a criterio del investigador contraindica la inyección intramuscular. - El participante tiene una función anormal del sistema inmune, excepto condiciones estables, como el HIV controlado. - El participante tiene una condición cardiovascular, respiratoria, hepática, neurológica, gastrointestinal, renal, o algún otro desorden que no esté estable a juicio del investigador en los 3 meses anteriores al screening o día 0. - Administración recurrente o crónica de medicación inmunosupresora. - El sujeto ha recibido inmunoglobulinas y/o productos derivados de la sangre 12 semanas antes de la vacunación (día 0) o espera recibirlos durante en estudio. - El participante ha recibido algún tipo de inmunoterapia (anticuerpos monoclonales, plasma) para prevenir el COVID-19 en los últimos 90 días antes de día 0. Los anticuerpos monoclonales para otras indicaciones estan permitidos. - Participación en alguna investigación que involucre productos en investigación (medicamento, biológico, equipo) en las 12 semanas antes de la vacunación y durante el transcurso del estudio. - El participante ha donado ≥ 450ml de sangre o productos derivador 12 semanas antes del screening. - El participante tiene alguna condición médica, que a juicio del investigador puede incrementar los riesgos del participante, interferir en el estudio o perjudicar la interpretación de los datos del estudio.