Clinical Trial of the COVID-19 Vaccine (Recombinant, Inactivated) in Brazil

The present protocol aims, to respond to several regulatory requirements to advance the clinical development of the product through a dose-escalation, controlled, randomized, adult clinical trial. The results of the Phase I (former Stage A), allow us to base the decision to evaluate the safety and immunogenicity of three doses of HDV-HXP-S (1μg, 3μg or 10μg).

Inclusion criteria

• Adults aged between 18 and 59 years at the time of consent;
• Agree to periodical contacts via phone, electronic means and home visits;
• Good health conditions (absence of a clinically significant medical condition, acute or chronic, determined by medical history, physical examination, and clinical evaluation by the investigator);
• Body Mass Index (BMI) of 17 to 40 kg/m² at the time of screening;
• Intention of participating in the study by signing the Informed Consent Form;
• A negative result for antibody testing against SARS-CoV-2 by CLIA performed within 7 days prior to study immunization;
• No history of COVID-19 diagnosed by RT-PCR or antigen testing at screening visit and therefore within 72 hours prior to study enrollment;
• No history of vaccination against COVID-19.

Exclusion criteria

• Use any product under investigation within 90 days prior to randomization or plan to use a product during the period of participation in the study;
• Have received vaccine in the last 28 days prior to inclusion in the study, or have immunization scheduled throughout the study period;
• Evidences of uncontrolled active neurological, cardiac, pulmonary, hepatic or renal disease, according to anamnesis or physical examination. Significant changes in treatment or hospitalizations due to worsening of the condition in the last three months are indicators of uncontrolled disease;
• Have a history of severe allergic reaction or anaphylaxis to the vaccine or study vaccine components;
• History of being allergic to chicken or eggs;
• History of angioedema or anaphylactic reaction;
• Have suspected or confirmed fever within 72 hours prior to vaccination or an axillary temperature above 37.8°C* on the day of vaccination (inclusion may be delayed until participant completes 72 hours without fever);
• Altered vital signs, clinically relevant in the opinion of the principal investigator;
• Neoplastic diseases (except basal cell carcinoma and cervical carcinoma in situ);
• Suspected or confirmed diseases with compromised immune system including: congenital or acquired immunodeficiencies and uncontrolled autoimmune diseases according to anamnesis or physical examination. Significant changes in treatment or hospitalizations due to worsening of the condition in the last three months are indicators of uncontrolled disease;
• Make use of immunosuppressive therapies six months prior to inclusion in the study or schedule use of immunosuppressants within two years of inclusion in the study. The dose of corticosteroids considered immunosuppressive is the equivalent to prednisone at a dose of 2,0 mg/kg/day for adults, for more than a week. The continuous use of topical or nasal corticosteroids is not considered immunosuppressive. The following therapies are considered immunosuppressive: antineoplastic drugs, radiotherapy, immunosuppressants to induce tolerance to transplants, among others.
• Have received blood products (transfusions or immunoglobulins) in the last three months prior to inclusion in the study, or schedule administration of blood products or immunoglobulins within two years of inclusion in the study.
• Have a history of bleeding disorders (e.g., clotting factor deficiency, coagulopathy, platelet dysfunction), or prior history of significant bleeding or bruising after IM injection or venipuncture;
• Have a history of any alcohol or drug abuse in the last 12 months prior to inclusion in the study that has caused medical, professional or family problems, as indicated by the clinical history;
• Behavioral, cognitive, or psychiatric illness that, in the opinion of the principal investigator or medical representative, affects the participant's ability to understand and collaborate with the requirements of the study protocol;
• The participant is a member of the team conducting the study or is in a dependent relationship with one of the members of the team conducting the study. Dependent relationships include close relatives (i.e., children, partner/spouse, siblings, parents), as well as employees or students who are directly dependent on the Researcher or local personnel conducting the study;
• Any other condition that, in the opinion of the principal investigator or medical representative, may jeopardize the safety or rights of a potential participant or prevent them from complying with this protocol.
• Abnormalities in screening laboratory tests considered to be exclusionary in the opinion of the principal investigator or medical representative. Grade 1 alterations are considered non-significant unless the principal investigator or medical representative indicates otherwise. If any alteration in the tests is considered temporary, the tests may be repeated in up to three opportunities during the screening period;
• Positive serological tests for the human immunodeficiency virus (ELISA anti-HIV1/2); Hepatitis B (HbsAg or Anti-HBc) or Hepatitis C (total ELISA anti-HCV);

For females:

• Pregnancy (confirmed by a positive β-hCG test), breastfeeding and/or expressing intention to engage in sexual practices with reproductive potential without using a contraceptive method in the three months following vaccination

• The temperature measured with a temporal thermometer is considered equivalent to the axillary temperature.