Safety and Immunogenicity Study of Recombinant Protein RBD Candidate Vaccine Against SARS-CoV-2 in Adult Healthy Volunteers (COVID-19)

Inclusion Criteria:

- Adults males or females between 18-39 years of age at the day of screening.

- Willing and able to comply with scheduled visits, laboratory test, complete diaries
and other study procedures.

- Body Mass Index 18 to 40 Kg/m2 at screening.

- COVID19 negative PCR test and negative serum IgG binding antibody response to the
SARS-CoV-2 S glycoprotein at screening or prior the first vaccination.

- Willing to avoid all other vaccines within 4 weeks before and after each injection.
Seasonal influenza vaccination is allowed if it is received at least 14 days before or
after the vaccination.

- Women of childbearing potential must have a negative pregnancy test in urine before
the inclusion of the study and prior to each vaccination.

- If female of childbearing potential, willing to use highly effective contraceptive
methods or have practiced sexual abstinence from the screening visit until 8 weeks
after the last injection.

- If male and not sterilized, willing to avoid impregnating female partners from
screening until 18 weeks after last injection.

- Willing and able to provide written informed consent prior the initiation of any study
procedures.

Exclusion Criteria:

- Pregnant or lactating or intending to become pregnant or plans to breastfeed during
the study.

- Positive pregnancy test at screening or prior to each vaccination.

- Any medical disease (acute, subacute, intermittent or chronic) or condition that in
the opinion of the investigator compromise the volunteer's safety, preclude
vaccination or compromise interpretation of the results.

- History of serious psychiatric condition likely to affect participation in the study
(e-g- ongoing severe depression, history of admission to an in-patient psychiatric
facility, recent suicidal ideation, history of suicide attempt, bipolar disorder,
personality disorder, alcohol and drug dependency, severe eating disorder, psychosis,
use of mood stabilisers or antipsychotic medication).

- History of respiratory disease (e.g., chronic obstructive pulmonary disease (COPD) and
asthma) requiring any daily medications currently or any treatment of respiratory
disease exacerbations (e.g., asthma exacerbation) in the last 5 years.

- History of significant cardiovascular disease including hypertension (e.g., congestive
heart failure, cardiomyopathy, ischemic heart disease) or history of myocarditis or
pericarditis as an adult.

- History of neurological or neurodevelopmental conditions (e.g., migraines, epilepsy,
stroke, seizures in the last 3 years, encephalopathy, focal neurologic deficits,
Guillain-Barré syndrome, encephalomyelitis or transverse myelitis).

- Ongoing malignancy or recent diagnosis of malignancy in the last five years excluding
basal cell and squamous cell carcinoma of the skin, which are allowed.

- Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV
infection; asplenia; recurrent severe infections.

- Any autoimmune or immunodeficiency disease/condition (iatrogenic or congenital).

- Acute illness within 72 hours prior each vaccination that in the opinion of the
investigator may interfere the evaluation of safety parameters.

- Usage of any investigational drug ≤ 90 days prior to study entry or plan to
participate in another research involving an investigational product
(drug/biologic/device) within 12 months after the first study vaccination.

- History of hypersensitivity or severe allergic reaction including anaphylaxis,
generalized urticarial, angioedema and other significant reactions related to food,
drugs, vaccines or pharmaceutical agents.

- History of allergic disease or reactions likely to be exacerbated by any component of
the COVID-19 vaccine HIPRA.

- Use of any immunosuppressant, glucocorticoids, or other immune-modifying drugs within
2 months prior to first study vaccination; or anticipation of the need for
immunosuppressive treatment within 6 months after last vaccination.

- Received immunoglobulin, blood-derived products, or other immunosuppressant drugs
within 90 days prior to first study vaccination.

- Known disturbance of coagulation (iatrogenic or congenital) or blood dyscrasias.

- Known bleeding disorder (e-g- factor deficiency, coagulopathy or platelet disorder),
or prior history of significant bleeding or bruising following IM injections or
venepuncture.

- Chronic liver disease.

- Positive test for HIV types 1 or 2 infection, hepatitis B surface antigen (HBsAg), or
hepatitis C virus antibodies (HCV Abs) at screening.

- Suspected or known current alcohol abuse or any other substances abuse (except
tobacco).

- History of COVID-19 infection.

- Receipt of medications intended to prevent COVID-19.

- Ever received an experimental vaccine against COVID-19.

- Close contact of anyone known to have SARS-CoV-2 infection within 15 days prior to
screening visit.

- Being directly involved in the conduct of the study.

- Any condition and/or laboratory finding that at the investigator consideration would
interfere with the study or put at risk the participant.