Pfizer vaccine recipients have lower neutralizing antibodies targeting delta variant up to three months after first dose. Outcome data needed to determine if this translates into less efficacy. Study concludes second dose interval needs to be shortened.

Medical Mythbusting Commentary for June 4, 2021

Pfizer vaccine recipients have lower antibodies targeting Indian variant – study
Pfizer-BioNTech vaccine recipients have lower antibody levels targeting the Delta variant

Neutralising antibody activity against SARS-CoV-2 VOCs B.1.617.2 and B.1.351 by BNT162b2 vaccination