We found no significant difference in cycle threshold values between vaccinated and unvaccinated, asymptomatic and symptomatic groups infected with SARS-CoV-2 Delta. Given the substantial proportion of asymptomatic vaccine breakthrough cases with high viral levels, interventions, including masking and testing, should be considered for all in settings with elevated COVID-19 transmission.
Competing Interest Statement
Dr. DeRisi reports being a scientific advisor to the Public Health Co. and a scientific advisor to Allen & Co. Dr. Havlir reports non-financial support from Abbott outside of the submitted work. The other authors declare no competing interests.
This work was supported by the Chan Zuckerberg Biohub, Healthy Yolo Together, the University of California, San Francisco, the Chan Zuckerberg Initiative, and The University of California, Davis.
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Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv