Frontiers in Public Health | |
Cellular and Humoral Immune Responses and Breakthrough Infections After Two Doses of BNT162b Vaccine in Healthcare Workers (HW) 180 Days After the Second Vaccine Dose | |
article | |
Alessandra Mangia1  Nicola Serra2  Giovanna Cocomazzi1  Vincenzo Giambra3  Stefano Antinucci4  Alberto Maiorana5  Francesco Giuliani6  Emanuele Montomoli7  Paolo Cantaloni8  Alessandro Manenti8  Valeria Piazzolla1  | |
[1] Liver Unit;Department of Public Health, University “Federico II”;Institute for Stem Cell Biology, Regenerative Medicine and Innovative Therapies;Allergy Diagnostic Section Euroimmun;GSSL Unit;ICT Innovation and Research Unit;Department of Molecular and Developmental Medicine, University of Siena;VisMederi Srl | |
关键词: SARS-CoV-2; mRNA vaccines; humoral response; IFN-γ; healthcare workers; | |
DOI : 10.3389/fpubh.2022.847384 | |
学科分类:社会科学、人文和艺术(综合) | |
来源: Frontiers | |
【 摘 要 】
Background Immunity and clinical protection induced by mRNA vaccines against SARS-CoV-2 have been shown to decline overtime. To gather information on the immunity profile deemed sufficient in protecting against hospitalization, we tested IgG levels, interferon-gamma (IFN-γ) secretion, and neutralizing antibodies 180 days (d180) after the second shot of BNT162b vaccine, in HW. Methods A total of 392 subjects were enrolled. All received BioNTech/Pfizer from February 2020 to April 2021. The vaccine-specific humoral response was quantitatively determined by testing for IgG anti-S1 domain of SARS-CoV-spike protein. Live virus microneutralization (MN) was evaluated by an assay performing incubation of serial 2-fold dilution of human serum samples, starting from 1:10 to 1:5120, with an equal volume of Wuhan strain and Delta VOC viral solution and assessing the presence/absence of a cytopathic effect. SARS-CoV-2-spike protein-specific T-cell response was determined by a commercial IFN-γ release assay. Results In 352 individuals, at d180, IgG levels decreased substantially but no results below the assay's positivity threshold were observed. Overall, 22 naive (8.1%) had values above the highest threshold. Among COVID-naive, the impact of age, which was observed at earlier stages, disappeared at d180, while it remained significant for 81 who had experienced a previous infection. Following the predictive model of protection by Khoury, we transformed the neutralizing titers in IU/ml and used a 54 IU/ml threshold to identify subjects with 50% protective immunity. Overall, live virus MN showed almost all subjects with previous exposure to SARS-CoV-2 neutralized the virus as compared to 33% of naive double-dosed subjects ( p 200 mIU/ml); among 271 naive, 7 (2.58%) and 17 (6.27%) subjects did not show borderline or strong secretion, respectively. Conclusions In naive subjects, low IgG titers are relatively long-lasting. Only a third of naive subjects maintain neutralizing responses. After specific stimulation, a very limited number of naive were unable to produce IFN-γ. The results attained in the small group of subjects with breakthrough infection suggest that simultaneous neutralizing antibody titers <20, binding antibody levels/ml <200, and IFN-γ <1,000 mIU/ml in subjects older than 58 may identify at-risk groups.
【 授权许可】
CC BY
【 预 览 】
Files | Size | Format | View |
---|---|---|---|
RO202301300003104ZK.pdf | 1435KB | download |