Early Immunogenicity and Safety of the Third Dose of BNT162b2 Messenger RNA Coronavirus Disease 2019 Vaccine Among Adults Older Than 60 Years: Real-World Experience.

Abstract

BACKGROUND:

Despite high vaccine coverage, an increase in breakthrough coronavirus disease 2019 (COVID-19) infections, prompted administration of a third BNT162b2 dose to people aged >60 years in Israel since July 2021. Here, we report real-world immunogenicity following third dose.

METHODS:

Overall, 208 healthcare workers aged >60 years were included. Paired pre- and post-second and/or third dose immunoglobulin G (IgG) and neutralizing antibody titers were compared. A subpopulation of low responders to the second dose was also tested for T-cell activation. For 25 paired serum samples, we tested neutralization of wild-type vs neutralization of Delta and Lambda variants, pre- and post-third dose. Active surveillance of vaccine adverse events was conducted through surveys.

RESULTS:

A pronounced immune response was observed following the third dose, including a 33-fold and 51-fold increase in IgG and neutralizing antibody, respectively. The neutralizing antibody levels post-third dose were 9.34 times higher than post-second dose (geometric mean titer, 2598 [95% confidence interval {CI}, 2085-3237] vs 207 [95% CI, 126-339]). Nine previously low responders had a significant antibody increase post-third dose, and 7 of 9 showed increase in T-cell activation. Additionally, sera obtained post-third dose highly and comparably neutralized the wild-type and Delta and Lambda variants. Of 1056 responders to the adverse-event survey, none had serious events.

CONCLUSIONS:

We demonstrate a rapid and broad immune response to the third BNT162b2 dose in individuals >60 years of age.

• Authors: Mayan Gilboa, Michal Mandelboim, Victoria Indenbaum, Yaniv Lustig, Carmit Cohen, Galia Rahav, Keren Asraf, Sharon Amit, Hanaa Jaber, Ital Nemet, Limor Kliker, Erez Bar-Haim, Ella Mendelson, Ram Doolman, Carmit Rubin, Gili Regev-Yochay, Yitshak Kreiss
• Journal: The Journal of infectious diseases (J Infect Dis) Vol. 225 Issue 5 Pg. 785-792 (03 02 2022) ISSN: 1537-6613 [Electronic] United States
• PMID: 34850049 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: [email protected].

Chemical References

• Antibodies, Neutralizing
• Antibodies, Viral
• COVID-19 Vaccines
• Immunoglobulin G
• RNA, Messenger
• BNT162 Vaccine

Topics

• Age Factors
• Aged
• Aged, 80 and over
• Antibodies, Neutralizing (blood)
• Antibodies, Viral (blood)
• BNT162 Vaccine (administration & dosage, adverse effects, immunology)
• COVID-19 (epidemiology, immunology, prevention & control)
• COVID-19 Vaccines (administration & dosage, adverse effects, immunology)
• Female
• Health Personnel
• Humans
• Immunogenicity, Vaccine
• Immunoglobulin G (blood)
• Male
• Middle Aged
• RNA, Messenger
• SARS-CoV-2