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Pfizer/BioNTech vaccine antibodies gone in many by seven months — Small US study

Six months after receiving the second dose of the two-shot vaccine from Pfizer and BioNTech, many recipients no longer have vaccine-induced antibodies that can immediately neutralise worrisome variants of the coronavirus, a study suggests.

Reuters reports that researchers analysed blood samples from 46 healthy, mostly young or middle-aged adults after receipt of the two doses and again six months after the second dose.

"Our study shows vaccination with the Pfizer-BioNtech vaccine induces high levels of neutralising antibodies against the original vaccine strain, but these levels drop by nearly 10-fold by seven months after the initial dose,” said Bali Pulendran of Stanford University and Mehul Suthar of Emory University.

In roughly half of all subjects, neutralising antibodies that can block infection against coronavirus variants such as Delta, Beta, and Mu were undetectable at six months after the second dose, their team reported last week  on bioRxiv ahead of peer review.

Neutralising antibodies are not the immune system's only defence against the virus. Still, they "are critically important in protecting against SARS-CoV-2 infection”, said Pulendran and Suthar. “These findings suggest that administering a booster dose at around six to seven months after the initial immunisation could enhance protection against SARS-CoV-2 and its variants.”

Study details

Durability of immune responses to the BNT162b2 mRNA vaccine

Mehul Suthar, Prabhu, Arunachalam, Mengyun Hu, Noah Reis, Meera Trisal, Olivia Raeber, Sharon Chinthrajah, Meredith E. Davis Gardner, Kelly Manning, Prakriti Mudvari, Eli Boritz, Sucheta Godbole, Amy R. Henry, Daniel C. Douek, Peter Halfmann, Yoshihiro Kawaoka, Veronika Zarnitsyna, Kari Nadeau, Bali Pulendran

Published on BioRXiv on 30 September 2021

Abstract
The development of the highly efficacious mRNA vaccines in less than a year since the emergence of SARS-CoV-2 represents a landmark in vaccinology. However, reports of waning vaccine efficacy, coupled with the emergence of variants of concern that are resistant to antibody neutralisation, have raised concerns about the potential lack of durability of immunity to vaccination. We recently reported findings from a comprehensive analysis of innate and adaptive immune responses in 56 healthy volunteers who received two doses of the BNT162b2 vaccination.

Here, we analysed antibody responses to the homologous Wu strain as well as several variants of concern, including the emerging Mu (B.1.621) variant, and T cell responses in a subset of these volunteers at six months (day 210 post-primary vaccination) after the second dose.

Our data demonstrate a substantial waning of antibody responses and T cell immunity to SARS-CoV-2 and its variants, at 6 months following the second immunisation with the BNT162b2 vaccine. Notably, a significant proportion of vaccinees have neutralising titers below the detection limit, and suggest a 3rd booster immunisation might be warranted to enhance the antibody titers and T cell responses.

 

BioRXiv article – Durability of immune responses to the BNT162b2 mRNA vaccine (Open access)

 

Reuters article – Pfizer/BioNTech vaccine antibodies disappear in many by 7 months (Open access)

 

See more from MedicalBrief archives:

 

Vaccine potency dips 11 percentage points over 8 months — HEROES-RECOVER

 

Biden administration wants boosters for most people 8 months after vaccination

 

Previous COVID prevents Delta infection better than Pfizer shot — Israel study

 

 

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