The purpose of this study is to evaluate the safety, immunogenicity, and efficacy of Nanocovax vaccine in volunteer subjects 18 years of age and older.

This is a phase 3, adaptive, multicenter, randomized, double-blind, placebo control study to evaluate the safety, immunogenicity, and efficacy of the Nanocovax vaccine against COVID-19 in volunteer subjects 18 years of age and older.

Age stratified as 18-45, 45-60, and > 60 years of age.

The assessment of immunogenicity will be further expanded in a subset of Phase 3 (1000 participants).

Randomly assigned to vaccine or placebo group with a ratio of 2:1 (2 subjects injected with Nanocovax 25 mcg : 1 subject injected with placebo).

Inclusion Criteria:

• Be a male or female 18 years of age or older.
• For females: Be of non-childbearing potential or willing to use appropriate contraceptive measures for 30 days prior to vaccination through 6 months after completion of the vaccine series.
• Willingness to provide a signed, printed, and dated informed consent form.
• Able and willing to participate in all activities in the clinical trial.
• Participants with HIV, HBV, HCV should have a health record, determined to be stable for 6 months prior to the screening.

Exclusion Criteria:

• Participants with unstable pre-existing medical conditions over the three months before enrollment (condition that has worsened to require hospitalization or significant changes in therapy).
• Planned administration/administration of a vaccine not foreseen by the study protocol from within 45 days before the first dose of study vaccine.
• Previous vaccination with any Covid-19 vaccine.
• History of COVID-19 disease.
• History of allergic reactions or anaphylaxis to previous immunizations or allergies to any components of the vaccine.
• Planning to become pregnant or planning to discontinue contraceptive precautions during the vaccination phase through 6 months after the second immunization.
• History of bleeding disorders/hemostasis or use of anticoagulants.
• Currently having cancer or undergoing cancer treatment.
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within 3 months prior to the first vaccine dose (inhaled and topical steroids are allowed).
• Women who are pregnant or breastfeeding.