Higher Antibody Concentrations in Health Care Workers Associated With Greater Reactogenicity Post-Vaccination

Background: Multiple factors may be associated with immune responses to SARS-CoV-2 vaccines. Factors potentially related to magnitude and durability of response include age, time, and vaccine reactogenicity. This study analyzed SARS-CoV-2 IgG spike antibody responses following the second dose of vaccine in healthcare workers (HCWs).Methods: Data were collected from participants enrolled in an IRB-approved longitudinal SARS-CoV-2 IgG serology study over a 12-month period (May 2020-May 2021). Participants were asked to complete a survey documenting number and severity of symptoms post-vaccination. Post-vaccination serology specimens were obtained at the last study time point one year after enrollment. Serum specimens were tested for SARS-CoV-2 IgG antibodies by using the Abbott Architect AdvisdeDx SARS-CoV-2 IgGII assay. Antibody levels were compared against time from second vaccine dose, and symptoms following vaccination.Findings: Altogether, 335 women (86.6%) and 52 men (13.4%) participated. Median age was 37 years (IQR 30 -43). Overall median antibody level was 2150.80 [1246.12, 3556.98] AU/mL (IQR). Age was not associated with a SARS-CoV2 IgG Spike antibody concentration (p-value = 0.10). Higher antibody responses (2253 AU/mL vs 1506 AU/mL; p = 0.008) were found in HCWs with one or more symptoms after the second dose of the vaccine (n=311).). Antibody responses persisted up to seven months post-vaccination; statistically significant decreases in antibody responses were observed over time (p 50 AU/mL. Higher antibody response was associated with increased reactogenicity to the vaccine. Age and sex were not associated with higher antibody responses.Funding: This study was funded by the Seattle Children’s Hospital Research Integration Hub and the Seattle Children’s Foundation. Acknowledgement: We acknowledge the Seattle Children’s Hospital staff who participated in this project.Funding Information: This study was funded by the Seattle Children’s Hospital Research Integration Hub and the Seattle Children’s Foundation.Declaration of Interests: Janet Englund has a is a consultant and receives grant funding from companies that may be affected by the research reported in the enclosed paper. We have disclosed those interests fully have in place an approved plan for managing any potential conflicts arising from that involvement. INCOMPLETEEthics Approval Statement: Approved by the Seattle Children’s Hospital Institutional Review Board.