A third dose of the Pfizer/BioNTech vaccine against COVID-19 has the potential to strongly improve protection against the Delta variant, more than the protection provided by the standard two dose regimen, suggest latest data released by Pfizer.

The data indicate that the levels of antibodies that protect against the Delta variant increase by about 5 times in individuals aged 18 to 55 years who receive a third dose of the vaccine. Additionally, among people aged 65 to 85 years, antibody levels that protect against Delta variant rise by 11-fold more than that after the second vaccine dose.

The data have not yet been peer-reviewed and it is unclear if the improved antibody levels actually correlate to better protection… (CNN, July 28, 2021)