Journal Article

Determinants of Anti-S Immune Response at 9 Months after COVID-19 Vaccination in a Multicentric European Cohort of Healthcare Workers—ORCHESTRA Project

Sala, Emma, Castelletti, Noemi, Negro, Corrado, De Palma, Giuseppe, Rodriguez-Suarez, Marta Maria, Janke, Christian, Fabianova, Eleonora, Feola, Daniela, Spiteri, Gianluca, Monaco, Maria Grazia Lourdes, Carrasco-Ribelles, Lucia A., Asafo, Shuffield S., Collatuzzo, Giulia, Sansone, Emanuele, Larese Filon, Francesca, Cegolon, Luca, Boffetta, Paolo, Abedini, Mahsa, Porru, Stefano, Toràn-Monserrat, Pere, Beresova, Jana, Lodi, Vittorio, Fernandez-Tardon, Guillermo, Ditano, Giorgia

2022

Overview

Background: The persistence of antibody levels after COVID-19 vaccination has public health relevance. We analyzed the determinants of quantitative serology at 9 months after vaccination in a multicenter cohort. Methods: We analyzed data on anti-SARS-CoV-2 spike antibody levels at 9 months from the first dose of vaccinated HCW from eight centers in Italy, Germany, Spain, Romania and Slovakia. Serological levels were log-transformed to account for the skewness of the distribution and normalized by dividing them by center-specific standard errors. We fitted center-specific multivariate regression models to estimate the cohort-specific relative risks (RR) of an increase of one standard deviation of log antibody level and the corresponding 95% confidence interval (CI), and combined them in random-effects meta-analyses. Finally, we conducted a trend analysis of 1 to 7 months’ serology within one cohort. Results: We included 20,216 HCW with up to two vaccine doses and showed that high antibody levels were associated with female sex (p = 0.01), age (RR = 0.87, 95% CI = 0.86–0.88 per 10-year increase), 10-day increase in time since last vaccine (RR = 0.97, 95% CI 0.97–0.98), previous infection (3.03, 95% CI = 2.92–3.13), two vaccine doses (RR = 1.22, 95% CI = 1.09–1.36), use of Spikevax (OR = 1.51, 95% CI = 1.39–1.64), Vaxzevria (OR = 0.57, 95% CI = 0.44–0.73) or heterologous vaccination (OR = 1.33, 95% CI = 1.12–1.57), compared to Comirnaty. The trend in the Bologna cohort, based on 3979 measurements, showed a decrease in mean standardized antibody level from 8.17 to 7.06 (1–7 months, p for trend 0.005). Conclusions: Our findings corroborate current knowledge on the determinants of COVID-19 vaccine-induced immunity and declining trend with time.

• Publisher: MDPI AG,MDPI
• Subject: Analysis / Antibodies / Antibodies, Viral / antibody level / confidence interval / Coronaviruses / COVID-19 / COVID-19 - prevention & control / COVID-19 infection / COVID-19 Vaccines / Female / females / Germany / Health aspects / Health Personnel / health services / Humans / Immune response / Immunity / immunization / Immunoassay / Infections / Italy / Medical personnel / meta-analysis / Public health / Regression analysis / Risk assessment / Romania / Serology / Severe acute respiratory syndrome coronavirus 2 / Slovakia / Sociodemographics / Spain / standard deviation / temporal trends / Vaccination / vaccine / vaccines