A cohort analysis of SARS-CoV-2 anti-spike protein receptor binding domain (RBD) IgG levels and neutralizing antibodies in fully vaccinated healthcare workers.
Clin Chem Lab Med
; 60(7): 1110-1115, 2022 06 27.
Article
in English
| MEDLINE | ID: covidwho-1817523
ABSTRACT
OBJECTIVES:
The waning of humoral immunity after COVID-19 vaccine booster (third dose) has not yet been fully evaluated. This study updates data on anti-SARS-CoV-2 spike protein receptor binding domain (S-RBD) binding antibodies (bAb) and neutralizing antibodies (NAb) levels in individuals with homologous vaccination 3-4 months after receiving the booster dose.METHODS:
Fifty-five healthcare workers (HCW) from Padova University-Hospital were asked to collect serum samples for determining antibodies (Ab) at 12 (t12) and 28 (t28) days, at 6 months (t6m) after their first Comirnaty/BNT162b2 inoculation, and 3-4 months after receiving the 3rd homologous booster dose. HCW were monitored weekly for SARS-CoV-2 infection. Ab titers were measured by two chemiluminescent immunoassays, one targeting the S-RBD immunoglobulin G (IgG), and one surrogate viral neutralization test (sVNT), measuring NAb.RESULTS:
Twenty of the HCW had natural COVID-19 infection (COVID+) at different times, before either the first or the second vaccination. Median S-RBD IgG and NAb levels and their interquartile ranges 3-4 months after the 3rd dose were 1,076 (529-3,409) kBAU/L and 15.8 (11.3-38.3) mg/L, respectively, for COVID-, and 1,373 (700-1,373) kBAU/L and 21 (12.8-53.9) mg/L, respectively, for COVID+. At multivariate regression analyses, with age and gender included as covariates, S-RBD IgG bAb and sVNT NAb levels were closely associated with the time interval between serological determination and the 3rd vaccine dose (log10 ßcoeff=-0.013, p=0.012 and log10 ßcoeff=-0.010, p=0.025) for COVID+, whereas no such association was found in COVID- individuals.CONCLUSIONS:
The third booster dose increases anti-SARS-CoV-2 Ab levels, elevated levels persisting for up to 3-4 months. Waning of Ab levels appears to be less pronounced for COVID+ individuals.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
SARS-CoV-2
/
COVID-19
Type of study:
Cohort study
/
Experimental Studies
/
Observational study
/
Prognostic study
Topics:
Vaccines
Limits:
Humans
Language:
English
Journal:
Clin Chem Lab Med
Journal subject:
Chemistry, Clinical
/
Laboratory Techniques and procedures
Year:
2022
Document Type:
Article
Affiliation country:
Cclm-2022-0322
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