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.
J Infect Dis
; 225(5): 785-792, 2022 03 02.
Article
in English
| MEDLINE | ID: covidwho-1722483
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.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Immunogenicity, Vaccine
/
COVID-19 Vaccines
/
COVID-19
/
BNT162 Vaccine
Type of study:
Experimental Studies
/
Observational study
Topics:
Vaccines
/
Variants
Limits:
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
English
Journal:
J Infect Dis
Year:
2022
Document Type:
Article
Affiliation country:
Infdis
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