This study is testing a new vaccine, called TI-0010, for COVID-19 in healthy adults aged 18-59. COVID-19 is a disease caused by the virus SARS-CoV-2. The vaccine is made by a company named Therorna Inc. and uses a special method called lipid nanoparticles (LNP), which are tiny particles that help deliver the vaccine into the body. Researchers want to see if the vaccine is safe and if it helps the body fight the virus.

People in the study will be split into groups called cohorts. Some will get a low dose and others a high dose. They will either get one or two shots in the arm. The study is randomized, meaning some people will get the vaccine and some will get a placebo, which is a fake shot. The study will check on participants' health several times over a year.

• Study lasts for about a year, with multiple follow-up visits.
• Participants must be 18-59 years old and healthy.
• There are risks, such as possible side effects from the vaccine.

Participants cannot join if they recently had COVID-19, are pregnant, or have certain health issues. They must also not have had a COVID-19 vaccine recently.