Can the COVID antibodies from the infection and the vaccination be distinguished?

The antibodies that develop after COVID-19 infection can usually be distinguished from those that develop after vaccination, although both types of antibodies appear similar.

In a natural COVID-19 infection, the immune system produces a wide range of antibodies against different proteins of the virus, such as the spike protein, the nucleocapsid protein, and other structural proteins. The spike protein is the main target for the vaccines.

Most COVID-19 vaccines target the spike protein of SARS-CoV-2. This means that the vaccine mainly stimulates antibodies against this specific protein. Vaccines such as Pfizer-BioNTech and Moderna produce antibodies specifically against the spike protein, while vaccines such as Johnson & Johnson also target the spike protein, but via a different mechanism (vector).

Tests have been developed that can specifically distinguish between antibodies generated by a natural infection and those generated by vaccination. These tests can detect whether there are antibodies against the nucleocapsid protein (which is present during infection) or only against the spike protein (which is present during vaccination).

Antibodies to the nucleocapsid protein are primarily produced after natural infection and are generally absent after vaccination with current COVID-19 vaccines that target only the spike protein. After infection, people often develop a broader immune response, including memory T cells and B cells.

Source: https://www.who.int/news-room/questions-and-answers/item/herd-immunity-lockdowns-and-covid-19

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106522/

Author: Prof. Dr. Dirk Devroey - Latest update: 2023-12-11 - Copyright: Clinifacts 2025