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

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.