P-1813. The natural history of respiratory viral antibodies during low circulation of respiratory viruses during the COVID-19 pandemic

Abstract Background Social distancing measures during the COVID-19 pandemic disrupted the circulation of most seasonal respiratory viruses (RV), providing an unprecedented opportunity to assess the waning of RV antibodies. Using a pan-viral immunosurvey, we assessed RV immunity during a prolonged time of low RV circulation at a population level.Figure 1.The longitudinal waning of respiratory viral antibodies during the COVID-19 pandemic.Linear mixed effect model for: (A) human metapneumovirus [HMPV], (B) influenza A, (C) influenza B , and (D) respiratory syncytial virus [RSV]. Each thin line represents a patient with geometric mean (gMean) epitope binding signal (EBS) at enrollment and end of study. Quartile 1 (purple) represents the patients with the highest gMean EBS at enrollment and quartile 4 (orange) represents the patients with the lowest gMean EBS. The thick lines represented predicted spline lines for each quartile based on the population.Figure 2.The log2-transformed fold changes in geometric mean epitope binding signal (EBS), a surrogate of antibody titer, for four different respiratory viruses.Boxplots show the distribution of log2-transformed fold changes in antibody levels for each virus: (A) Human metapneumovirus (HMPV), (B) Influenza A, (C) Influenza B, and (D) Respiratory Syncytial Virus (RSV). Individual points represent participant-level values. A log2 fold change of 0 indicates no change in antibody level; values below 0 indicate waning, while values above 0 indicate an increase. Comparisons between quartile 1 and quartile 4 were assessed using the Wilcoxon rank-sum test. All comparisons had a p