R Li, H Liu, CK Fairley, Z Zou, L Xie, X Li, M Shen, Y Li… - medRxiv, 2021 - medrxiv.org
Background Over 86% of older adults aged≥ 65 years are fully vaccinated against SARS-
COV-2 in the United States (US). Waning protection of the existing vaccines promotes the …