mix and match heterologous prime-boost study using approved covid-19 vaccines

Conditions: Covid19

Summary: this is an observer-blind, randomized study which aims to assess the immune response and the safety of two different approved vaccines for first and second dose in healthy adults.

this is a phase 2, observer-blind, randomized study to assess the safety and the immunogenicity of heterologous prime-boost covid-19 vaccines regimens in healthy adults aged 18 to 65 years using two approved vaccines (sinopharm / cnbg vaccine (bbibp-corv) and johnson \& johnson vaccine (ad26.cov2.s)). the study will consist of 2 cohorts, one for main immunology endpoints (n=260, 65 per study arm) and one for more detailed immunological assessment (n=100, 25 per study arm). two doses of vaccine will be administered intramuscularly 4 week apart. all the study participants will be follow-up for 12 months from the administration of first vaccine dose.

Eligibility criteria:
inclusion criteria: * individuals aged 18 to 65 years old at the time of consent. * residing within the area of the study and planning to stay for the study duration. * hiv negative test result on the day of screening (for those who do not have a documented hiv test results in the last three months of screening). * female volunteers of childbearing potential with a negative pregnancy test on the day(s) of screening and vaccination, practicing/willing to practice continuous effective contraception\* recommended by the national health system up to 12 weeks after the booster vaccination.. * agreement to refrain from blood donation during the course of the study. * able and willing to comply with all study requirements, based on the assessment of the investigator. * willingness to provide written informed consent before any trial procedure \* effective contraception is defined as follows: contraceptive medications delivered orally, intramuscularly, vaginally, or implanted underneath the skin, surgical methods (hysterectomy or bilateral tubal ligation), condoms, diaphragms, intrauterine device (iud), and abstinence. exclusion criteria: * pregnancy, lactation, or intention to become pregnant during the vaccination phase through three months after the booster dose. * prior receipt/ planned receipt of any vaccine other than the study intervention within 28 days before and after each study vaccination. * previous participation in any covid-19 vaccination trial or vaccination campaign. * administration of immunoglobulins and/ or any blood products within the three months preceding the administration of the study vaccine. * known infection with hepatitis b, c virus. * known history of allergy or anaphylaxis to study vaccine components and/or excipients or other medications, or any other allergies deemed by the investigator to increase the risk of an adverse reaction. * history of bleeding disorder (e.g., factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following im injections or venipuncture. * continuous use of the anticoagulants, such as coumarins and related anticoagulants. * severe and/or uncontrolled cardiovascular disease, respiratory disease, gastrointestinal disease, renal disease, liver disease, endocrine disorders, and neurological illness (mild/moderate well controlled comorbidities are allowed). * any clinically significant abnormal finding on screening as judged by the investigator. * confirmed sars-cov-2 infection at enrollment. * any confirmed or suspected immunosuppressive or immunodeficient state, asplenia, recurrent severe infections and chronic use (more than 14 days) immunosuppressant medication within 3 months prior to recruitment (topical steroids are allowed). * any other finding which in the opinion of the investigators would increase the risk of an adverse outcome from participation in the trial or result in incomplete or poor-quality data.

Keywords: sars-cov-2, vaccines, mix and match trial