biostudies-literatureBents SJNIAID NIH HHSWellcome Trust11015https://www.ebi.ac.uk/biostudies/studies/S-EPMC12695953biostudies-literatureUnknown16(1)The rebound of endemic respiratory viruses following the COVID-19 pandemic was marked by atypical transmission dynamics, with children experiencing increased disease burden and out-of-season epidemics as restrictions relaxed. Here we used serology from a newly developed quantitative multiplex assay to assess the post-pandemic immunity debt. We assessed age-specific antibody dynamics across a broad range of respiratory viruses, including influenza, respiratory syncytial virus, seasonal coronaviruses, and SARS-CoV-2 using serology collected in King County, Washington, US, from 2020-2022 (n = 1508). We found that respiratory virus immunodynamics differed between individuals <5 years of age and older individuals, with young children experiencing larger boosts and quicker waning of antibodies aNature communicationsMultiplex serology reveals age-specific immunodynamics of respiratory pathogens in the wake of the COVID-19 pandemic.PMC1269595375N93021C00015225001/Z/22/ZHansen CBlazevic RHan PBents SJWaghmare AAndrews CKimball LEnglund JABoeckh MStevens-Ayers TStarita LAdler AWolter NPrentice RMoyes JMartin ETKrantz EMViboud CPerofsky ACvon Gottberg ACohen CHay JAMaake LfalseMultiplex serology reveals age-specific immunodynamics of respiratory pathogens in the wake of the COVID-19 pandemic.The rebound of endemic respiratory viruses following the COVID-19 pandemic was marked by atypical transmission dynamics, with children experiencing increased disease burden and out-of-season epidemics as restrictions relaxed. Here we used serology from a newly developed quantitative multiplex assay to assess the post-pandemic immunity debt. We assessed age-specific antibody dynamics across a broad range of respiratory viruses, including influenza, respiratory syncytial virus, seasonal coronaviruses, and SARS-CoV-2 using serology collected in King County, Washington, US, from 2020-2022 (n = 1508). We found that respiratory virus immunodynamics differed between individuals <5 years of age and older individuals, with young children experiencing larger boosts and quicker waning of antibodies a2025-01-01T00:00:00Z2025 Dec2026-06-07T05:03:10.135Z2026-06-07T03:06:27.023ZS-EPMC126959534137212710.1038/s41467-025-65957-9