Linear mixed-effects model for the analysis of antibody kinetics following vaccination with BNT162b2 mRNA COVID-19 vaccine. Cohort of health care workers

• Autor(a) principal: Silva, Joana Maria Rocha Fernandes Oliveira e
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/152854
• topic: Linear mixed-effects model; antibody kinetics; BNT162b2 mRNA vaccine; COVID-19; Domínio/Área Científica::Ciências Naturais::Matemáticas

Introduction: In December 2020, healthcare workers (HCW) started being vaccinated against COVID-19 with the BNT162b2 mRNA vaccine. Objectives: To analyze humoral kinetics over 10 months and the effect of gender, age and prevaccination antibody (Ab) levels in vaccination against COVID-19. Methods: In a university hospital center, HCW were able to measure anti-spike IgG (SARS-CoV- 2 IgG II Abbott assay) at 5 time points: up to 72 hours pre-vaccination (T0) and post-vaccination at 15 days (T1), 3, (T2) 6 (T3) and 10 months (T4). HCW who completed vaccination scheme and with T0 Ab assessment, where included. We modeled the decrease in log10 transformed Ab levels, with a linear mixed-effects model. We included as covariates time (months), gender, age and presence of Ab >50 AU/ml pre-vaccination (naïve vs non-naïve). We compared the models with different covariates with the AIC. Significance was set at 0.05. We performed the analysis with the R software. Results: 4443 HCW participated (mean age 43.9 years, 75% female). After vaccination, Ab values increased significantly (Median (Md) <6.8 AU/ml vs 20.9x103 AU/ml IQR 13.0-32.1x103 AU/ml, P<0.001) and progressively decreased over 10 months (Md 600 AU/ml IQR 400-1000 AU/ml, P<0.001). Women, young and non-naïve HCW showed higher values at T1, T2, T3 and T4. The final model included random effects for the origin and slope. Gender, age, and pre-vaccination status independently contributed to IgG values (estimated coefficient for female gender 0.07, P<0.001; age (1 year) -0.001, P<0.001; non-naïve 0.23, P<0.001). Ab decreased by an average of 0.16/month (P<0.001). Non-naïves declined more slowly (interaction with time 0.04, P<0.001). Discussion/Conclusion: Our data support evidence regarding post-vaccination Ab kinetics. Serological assessment can guide the need for boosters in groups prone to lower titers.