Unfortunately, information about antibodies after vaccination are still developing, what is known is that COVID-19 vaccines are safe and effective at preventing COVID-19. COVID-19 vaccines are effective against severe disease and death from variants of the virus that causes COVID-19, including the Delta variant.
The presence or absence of antibodies after covid infection or vaccination does not necessarily mean you are immune from SARS-CoV-2 infection, as it is not known whether having antibodies to SARS-CoV-2 will protect you from getting infected again. It also does not indicate whether you can infect other people with SARS-CoV-2. Antibody tests are not recommended to determine your level of immunity or protection from COVID-19.