The vaccinated may be silent “super spreaders.”

“A: It is not known if the vaccine protects against asymptomatic SARS-CoV-2 infection.”

Source

Q: If a person has received the Pfizer-BioNTech COVID-19 Vaccine, will the vaccine protect against transmission of SARS-CoV-2 from individuals who are infected despite vaccination?

A: Most vaccines that protect from viral illnesses also reduce transmission of the virus that causes the disease by those who are vaccinated. While it is hoped this will be the case, the scientific community does not yet know if the Pfizer-BioNTech COVID-19 Vaccine will reduce such transmission.

Source

This study was published in July 2021: Vaccinated and unvaccinated individuals have similar viral loads in communities with a high prevalence of the SARS-CoV-2 delta variant