Peptide Antigen - Amino Acid Sequence
"the antigen to which the immune system responds is a relatively small number of amino acids or peptide.
A possible alternative approach to immunization would therefore be to identify the peptide sequences that trigger a protective immune response and to use completely synthetic versions of these as the vaccine substance"
https://www.who.int/teams/health-product-policy-and-standards/standards-and-specifications/vaccine-standardization/synthetic-peptide-vaccines
"Peptide antigen, namely, a peptide used to trigger animal's immune system to develop antibodies specific to that peptide. Nowadays, the use of synthetic peptide antigens as immunogens has markedly increased, and this technique is also widely applied for immune research"
https://www.creative-peptides.com/services/peptide-antigen-design.html
Viral Load - Peptide Antigen Sequences
"at peak infection, a person can have 1 billion to 10 billion virions in their body."
https://biology.stackexchange.com/questions/100592/how-many-mrna-strands-are-in-a-single-dose-of-the-covid-19-vaccines
Antigen = Pathogen Parts (Protein)
"An antigen is a molecule that stimulates an immune response by activating leukocytes (white blood cells) that fight disease. Antigens may be present on invaders, such as bacteria, viruses, parasites, fungi, and transplanted organs, or on abnormal cells, such as cancer cells."
https://www.verywellhealth.com/what-is-an-antigen-5083801
Synthetic Peptide Vaccine
"vaccines can be mainly classified by how the antigen, active component, that produces a specific immune response against the disease-causing organism, are prepared."
https://www.vedantu.com/biology/vaccine