Immune responses to SARS-CoV-2 in three children of parents with symptomatic COVID-19
Shidan Tosif, Melanie R. Neeland, Philip Sutton, Paul V. Licciardi, Sohinee Sarkar, Kevin J. Selva, Lien Anh Ha, Celeste M. Donato, Zheng Quan Toh, Rachel A. Higgins, Carolien E. van de Sandt, Melissa M. Lemke, Christina Y. Lee, Suzanne K. Shoffner, Katie L. Flanagan, Kelly B. Arnold, Francesca L. Mordant, Kim Mulholland, Julie E. Bines, Kate Dohle, Daniel G. Pellicci, Nigel Curtis, Sarah McNab, Andrew C. Steer, Richard Saffery, Kanta Subbarao, Amy W. Chung, Katherine Kedzierska, David Burgner, Nigel W. Crawford
Abstract
Compared to adults, children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have predominantly mild or asymptomatic infections, but the underlying immunological differences remain unclear. Here, we describe clinical features, virology, longitudinal cellular, and cytokine immune profile, SARS-CoV-2-specific serology and salivary antibody responses in a family of two parents with PCR-confirmed symptomatic SARS-CoV-2 infection and their three children, who tested repeatedly SARS-CoV-2 PCR negative. Cellular immune profiles and cytokine responses of all children are similar to their parents at all timepoints. All family members have salivary anti-SARS-CoV-2 antibodies detected, predominantly IgA, that coincide with symptom resolution in 3 of 4 symptomatic members. Plasma from both parents and one child have IgG antibody against the S1 protein and virus-neutralizing activity detected. Using a systems serology approach, we demonstrate higher levels of SARS-CoV-2-specific antibody features of these family members compared to healthy controls. These data indicate that children can mount an immune response to SARS-CoV-2 without virological confirmation of infection, raising the possibility that immunity in children can prevent the establishment of SARS-CoV-2 infection. Relying on routine virological and serological testing may not identify exposed children, with implications for epidemiological and clinical studies across the life-span.