Delta variant: Pfizer’s vaccine efficacy drops faster than AstraZeneca

The effectiveness of the Pfizer/BioNtech vaccine declines more rapidly than the Oxford vaccine — AstraZeneca — against the delta variant, according to a study by researchers at the University of Oxford.

Before reaching this conclusion, the British scientists, who were involved in the production of one of the worshipers, between December 2020 and August 2021, examined samples taken from more than 700,000 people, according to AFP.

After one month, for infections with a high viral load, an individual who received their second dose of the vaccine developed by Pfizer’s laboratory was 90% more protected from the delta variant of coronavirus than the unvaccinated person.

78% efficiency for Pfizer after three months

After two months this number drops to 85% and then to 78% after three months. Individuals who received two injections of the AstraZeneca vaccine had 67% protection after one month, 65% after two months and 61% after three months.

After four to five months, the level of protection for these two vaccines becomes similar, note the authors of this study that, so far, has not been validated by their peers.

These numbers “really represent a decline” in the effectiveness of the Pfizer vaccine, said Dr. Quinn Boyles, who participated in the study, which was published on Thursday, August 19.

Vaccine efficacy ‘still very high’

Regarding the AstraZeneca vaccine, “the differences (from month to month) are due to chance, i.e. there can be no change in protection.”

However, despite “these slight decreases in protection,” the doctor said, “the overall efficacy (for the serums) remains very high.”

He also stressed that the researchers studied the overall protection, not the level of protection against severe forms and hospitalization, “which are very important data for evaluating the efficacy of vaccines.”