Predictors for reactogenicity and humoral immunity to SARS-CoV-2 following infection and mRNA vaccination: A regularized, mixed-effects modelling approach

BackgroundThe influence of pre-existing humoral immunity, inter-individual demographic factors, and vaccine-associated reactogenicity on immunogenicity following COVID vaccination remains poorly understood.MethodsTen-fold cross-validated least absolute shrinkage and selection operator (LASSO) and linear mixed effects models were used to evaluate symptoms experienced during natural infection and following SARS-CoV-2 mRNA vaccination along with demographics as predictors for antibody (AB) responses in COVID+ participants in a longitudinal cohort study.ResultsIn previously infected individuals, AB were more durable and robust following vaccination when compared to natural infection alone. Higher AB were associated with experiencing dyspnea during natural infection, as was the total number of symptoms reported during the COVID-19 disease course. Both local and systemic symptoms following 1st and 2nd dose of SARS-CoV-2 mRNA vaccines were predictive of higher AB after vaccination, as were the demographic factors of age and Hispanic ethnicity. Lastly, there was a significant temporal relationship between AB and days since infection or vaccination.ConclusionVaccination in COVID+ individuals ensures a more robust immune response. Experiencing systemic and local symptoms post-vaccine is suggestive of higher AB, which may confer greater protection. Age and Hispanic ethnicity are predictive of higher AB.