[1] Kaiser Permanente Ctr Hlth Res, 3800 N Interstate Ave, Portland, OR 97227 USA
[2] Univ Washington, Dept Med, Seattle, WA USA
[3] Ctr Dis Control & Prevent, Coronavirus & Other Viral Resp Dis Div, Natl Ctr Immunizat & Resp Dis, Atlanta, GA USA
[4] Seattle Childrens Res Inst, Seattle, WA USA
[5] Univ Washington, Dept Pediat, Seattle, WA 98195 USA
[6] Univ Washington, Dept Epidemiol, Seattle, WA 98195 USA