Efficacy, Immunogenicity and Safety of BBIBP-CorV Vaccine Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection.

To expand the access and delivery of COVID-19 Vaccines in Africa (ECOVA), the investigators will conduct a phase 3, individually randomized, observer-blind, controlled (influenza vaccine) trial to evaluate the safety and efficacy of the BBIBP-CorV vaccine against any severe acute respiratory syndrome 2 (SARS-CoV- 2) infection among adults 18 years and older. The BBIBP-CorV vaccine is an inactivated SARS-CoV-2 vaccine (Vero cell) manufactured by the Beijing Institute of Biological Products (BIBP), China National Biotec Group (CNBG), Sinopharm, Beijing, People's Republic of China and received emergency use authorization (EUA) from World Health Organization (WHO).

The investigators will conduct a randomized, observer-blind, controlled, phase 3 trial will be conducted to assess the safety, immunogenicity and efficacy of two doses of intramuscular BBIBP-CorV vaccine, followed by a booster dose, in adults 18 years of age and older. . Study Arms 1 and 2 will have two groups: group 1 - HIV-uninfected receiving BBIBP-CorV or Flu Quadrivalent; group 2 - HIV-infected receiving BBIBP-CorV or Flu Quadrivalent. Arm 3 will have 1 group - HIV-uninfected co-administration group receiving both vaccines. The randomization will be stratified by HIV status. Active surveillance for covid-19 will be carried out and immunogenicity will be assessed for a subset of population.

Eligibility Criteria:
Inclusion Criteria:

* Female and male adults aged 18 years and older (Arm 1-Group 1 and Arm 2-Group 1) and 18-65 years (Arm 1 - Group 2, Arm 2-Group 2 and Arm3-Group1) at the time of consent.
* Residing within the Beira and Maputo health region and planning to stay for the study duration.
* HIV-negative test result at the day of screening for participants in Group 1, in Arms 1, 2 and 3
* HIV-positive and on anti-retroviral treatment for at least six months for participants in Group 2, in Arms 1 and 2
* 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 four weeks after the third vaccination.
* Able and willing to comply with all study requirements, based on the assessment of the investigator.
* Provide written informed consent before any trial procedure.

Exclusion Criteria:

* Pregnant, lactating, or with intention to become pregnant during the study.
* Planned receipt of any investigational vaccine than the study intervention within 28 days before and after each study vaccination.
* Active COVID-19 infection at the time of enrollment
* History of allergic reactions or anaphylaxis to previous immunization or allergies to any components of the vaccines.
* History of bleeding disorder, or prior history of significant bleeding or bruising following intramuscular injections or venipuncture (for the immunogenicity subset and HIV infected participants).
* 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.