AUTHOR=Collatuzzo Giulia , Visci Giovanni , Violante Francesco S. , Porru Stefano , Spiteri Gianluca , Monaco Maria Grazia Lourdes , Larese Fillon Francesca , Negro Corrado , Janke Christian , Castelletti Noemi , De Palma Giuseppe , Sansone Emanuele , Mates Dana , Teodorescu Silvia , Fabiánová Eleonóra , Bérešová Jana , Vimercati Luigi , Tafuri Silvio , Abedini Mahsa , Ditano Giorgia , Asafo Shuffield S. , Boffetta Paolo , Orchestra WP5 Working Group , Zunarelli Carlotta , Bonfiglioli Roberta , Carta Angela , Verlato Giuseppe , Lippi Giuseppe , Gibellini Davide , Pezzani Maria Diletta , Torroni Lorena , Hoelscher Michael , Wieser Andreas , Reinkemeyer Christina , Plank Michael , Noreña Ivan , Rubio-Acero Raquel , Winter Simon , Leustean Mihaela , Perseca Ovidiu , Ipate Madalina , Rascu Agripina , Strhársky Jozef , Hellebrandt Petra , Križanová Daniela , Mrázová Marianna , De Maria Luigi , Sponselli Stefania , Stefanizzi Pasquale , Caputi Antonio TITLE=Determinants of anti-S immune response at 6 months after COVID-19 vaccination in a multicentric European cohort of healthcare workers – ORCHESTRA project JOURNAL=Frontiers in Immunology VOLUME=13 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.986085 DOI=10.3389/fimmu.2022.986085 ISSN=1664-3224 ABSTRACT=Background

The duration of immune response to COVID-19 vaccination is of major interest. Our aim was to analyze the determinants of anti-SARS-CoV-2 IgG titer at 6 months after 2-dose vaccination in an international cohort of vaccinated healthcare workers (HCWs).

Methods

We analyzed data on levels of anti-SARS-CoV-2 Spike antibodies and sociodemographic and clinical characteristics of 6,327 vaccinated HCWs from 8 centers from Germany, Italy, Romania and Slovakia. Time between 1st dose and serology ranged 150-210 days. Serological levels were log-transformed to account for the skewness of the distribution and normalized by dividing them by center-specific standard errors, obtaining standardized values. We fitted center-specific multivariate regression models to estimate the cohort-specific relative risks (RR) of an increase of 1 standard deviation of log antibody level and corresponding 95% confidence interval (CI), and finally combined them in random-effects meta-analyses.

Results

A 6-month serological response was detected in 99.6% of HCWs. Female sex (RR 1.10, 95%CI 1.00-1.21), past infection (RR 2.26, 95%CI 1.73-2.95) and two vaccine doses (RR 1.50, 95%CI 1.22-1.84) predicted higher IgG titer, contrary to interval since last dose (RR for 10-day increase 0.94, 95%CI 0.91-0.97) and age (RR for 10-year increase 0.87, 95%CI 0.83-0.92). M-RNA-based vaccines (p<0.001) and heterologous vaccination (RR 2.46, 95%CI 1.87-3.24, one cohort) were associated with increased antibody levels.

Conclusions

Female gender, young age, past infection, two vaccine doses, and m-RNA and heterologous vaccination predicted higher antibody level at 6 months. These results corroborate previous findings and offer valuable data for comparison with trends observed with longer follow-ups.