New COVID booster vaccine shows promise in early trial

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Part A: Healthy individuals aged 18 to 54 with completed primary vaccination schedule for COVID-19 with CoronaVac®. Have received a booster dose with Comirnaty® between 9 and 15 months before inclusion in the study. Part A2: Healthy individuals aged 55 to 85 with a completed vaccination schedule for COVID-19 with CoronaVac® or Covishield® for at least six months from inclusion in the study. Have received at least one booster dose with Comirnaty® or Covishield® at least six months ago. Part B: Healthy individuals aged 18 to 85 who completed the vaccination schedule for COVID-19 with CoronaVac® or Covishield® for at least six months from inclusion in the study. Have received at least one booster dose with Comirnaty® or Covishield® at least six months ago. All Parties: * Consent to the study and its procedures, documented by signing the Free and Informed Consent Form (TCLE). * Present good general health as determined by medical examination. * Agree not to donate blood while participating in the study. * Women of childbearing potential must agree to use acceptable contraception\* for at least 30 days before initiation of vaccination and at least 90 days following the use of the investigational product or active comparator. * Acceptable contraceptive methods: Barrier methods, including condoms or cervical caps. Surgically sterile partner/participant (including those undergoing vasectomy, hysterectomy, bilateral oophorectomy, and or tubal ligation) who is the only partner. Intrauterine device (with or without hormones) implanted. Birth control medications (oral, topical, injectable, or implantable). True sexual abstinence is in line with the patient's preferred and usual lifestyle. Note: periodic abstinence, such as calendar, ovulation, symptothermal, post-ovulation, or coitus interruptus methods, will not be considered a valid method. Exclusion Criteria: Part A: * No previous history or acute infection with SARS-CoV-2. Previous records will be considered self-declaration by the participant. * Vaccination booster for COVID-19 less than nine months ago and more than 15 months after inclusion in the study. * The presence of comorbidities or any condition that, in the study investigator's assessment, could put the participant at risk or create a confounding factor in the study, including clinically stable chronic diseases. Part A2: * Acute SARS-CoV-2 infection or less than six months from the date of inclusion in the study. * Vaccination booster for COVID-19 less than six months ago. * The presence of comorbidities or any condition that, in the study investigator's assessment, could put the participant at risk or create a confounding factor in the study, including clinically stable chronic diseases. Part B: * Acute or SARS-CoV-2 infection or less than six months from the date of inclusion. * Vaccination booster for COVID-19 less than six months ago. * Any condition that, in the assessment of the study investigator, could put the participant at risk or create a confounding factor in the study. Diseases such as diabetes, hypertension, and clinically stable neuralgia may not constitute an exclusion criterion as determined by the medical investigator. All Parties: * Have received primary vaccination with Janssen or Comirnaty® vaccine. * Have received a booster vaccine with the Janssen or CoronaVac® vaccine. * History of SAE after administration of a COVID-19 vaccine. * History of thrombophilia. * Being on anticoagulant therapy or having a bleeding disorder that contraindicates intramuscular injection. * Positive serology for HIV, HBV (HBsAg) or HCV. * Laboratory abnormality in blood count, biochemistry, or urine tests. Exception will be defined by the clinical investigator when evaluated together with the participant's medical history. * Women who are pregnant, breastfeeding, or intend to become pregnant/breastfeed within three months of inclusion in the study. * Evidence of clinically active disease such as, but not limited to: neurological, renal, cardiovascular, endocrine, pulmonary, hepatic, hematological, immunological (including autoimmunities and immunodeficiencies), neoplastic or infectious disease. * Psychiatric illness or cognitive impairment that, in the investigator's judgment, may affect the participant's ability to engage in the clinical trial following the established agenda. * Alcohol abuse or use of illicit drugs in the last 12 months before recruitment has caused any family, medical, or professional problems. * History of severe allergic reaction or anaphylaxis to any component of the vaccine. * History of asplenia. * Have participated in any other experimental clinical trial in the 12 months before inclusion or intend to participate in any experimental clinical trial in the 12 months following participation. * Plans to participate in other clinical studies concurrently with this one. Use of some immunosuppressive therapy three months before recruitment or planning its use within three months after vaccination, including use of corticosteroids or other immunosuppressive medication (note: the immunosuppressive dose of corticosteroids is equivalent to 20 mg/day of prednisone per more than a week (topical or nasal corticosteroids are not considered immunosuppressive). * Use of blood products (blood or immunoglobulins) within three months before inclusion or indication of their use during the study. * Suspected active infection or confirmed fever (axillary temperature ≥ 38.0 oC) within 72 hours before inclusion. Recruitment should be delayed until the participant remains fever-free for 72 hours. * Have received any live attenuated or inactivated vaccine within 28 days or 14 days, respectively, before use of the investigational product or active comparator or planning immunization within 28 days of study inclusion. * History of use of medication authorized by ANVISA intended to prevent or treat COVID-19 less than six months before the study's inclusion date.