1102. The Host Response to SARS-CoV-2 Infection Differs by Age
Authors: Parsons Emily , Richard Stephanie A , Laing Eric D , Fries Anthony C , Livezey Jeffrey , Jones Milissa , Lindholm David A , Mende Katrin , Rozman Julia S , Ganesan Anuradha , Huprikar Nikhil , Lalani Tahaniyat , Smith Alfred G , Mody Rupal , Bazan Samantha , Saunders David , Colombo Rhonda E , Colombo Christopher , Ewers Evan C , Larson Derek , Maves Ryan C , Berjohn Catherine M , Maldonado Carlos , Simons Mark P , Tribble David , Agan Brian , Burgess Timothy , Pollett Simon , Malloy Allison M 
Published: December 2022

Abstract

Background
Infection with SARS-CoV-2 and the resulting host immune response has been primarily characterized in middle and older aged populations due to a higher incidence of symptoms in these age groups. Due to reduced severity of disease, children were poorly studied and assumed to be less frequently infected compared to older age groups. We measured the viral load and adaptive immune response across the age-spectrum to define the age-dependent viral and host responses.

Methods
From March 2020-March 2022, we enrolled individuals across the age spectrum who presented to U.S. military medical treatment facilities with COVID-19-like symptoms. In this longitudinal cohort study, demographic and clinical data were collected in addition to nasopharyngeal swabs and peripheral blood. Magnitude of viral RNA was measured by quantitative PCR (qPCR) from nasopharyngeal samples and SARS-CoV-2-specific IgG antibodies were measured from blood with multiplex microsphere immunoassays.

Results
4,768 SARS-CoV-2 positive participants were enrolled, among whom 42, 64, 89, 380, 948 and 245 individuals were in age brackets 0-4y, 5-11y, 12-17y, 18-44, 45-64y, and &gt;65y, respectively. Viral load as measured by qPCR was determined to be similar across age groups within the first week post symptom onset. The magnitude of the IgG antibody response against the spike protein was also compared across age groups at early and convalescent time points and was higher in those over the age of 65 years.

Conclusion
Early viral load during acute infection did not correlate with age in individuals who experienced COVID-19. These findings diverge from other respiratory viruses, such as respiratory syncytial virus and influenza where children tend to have higher viral loads. In contrast, the magnitude of the antibody response against the spike protein correlated with older age at acute and convalescent time points. Together our data suggest that the host response against SAR-CoV-2 differs with age and is not associated with the acute viral load. Defining age-dependent immunity against SARS-CoV-2 has the potential to identify key immunologic responses that can be used to optimize treatment and vaccine strategies.

Disclosures
Julia S. Rozman, n/a, Astra Zeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response Ryan C. Maves, MD, AiCuris: Grant/Research Support|Sound Pharmaceuticals: Grant/Research Support|Trauma Insights, LLC: Advisor/Consultant Mark P. Simons, PhD, AstraZeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response David Tribble, MD, DrPH, Astra Zeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response Timothy Burgess, MD, MPH, AstraZeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response Simon Pollett, MBBS, Astra Zeneca: The HJF, in support of the USU IDCRP, was funded to conduct or augment unrelated Phase III Mab and vaccine trials as part of US Govt. COVID19 response.