The purpose of this Phase 1 study is to assess the safety and reactogenicity of Ad26.COV2.S administered intramuscularly (IM) at 2-dose levels, as a 2-dose schedule in 250 healthy participants aged greater than or equal to 20 to less than or equal to 55 years and greater than or equal to 65 years in good health with or without stable underlying conditions.

This study is completed without published results.