Viral Load Among Vaccinated and Unvaccinated, Asymptomatic and Symptomatic Persons Infected With the SARS-CoV-2 Delta Variant

Charlotte B Acharya; John Schrom; Anthea M Mitchell; David A Coil; Carina Marquez; Susana Rojas; Chung Yu Wang; Jamin Liu; Genay Pilarowski; Leslie Solis; Elizabeth Georgian; Sheri Belafsky; Maya Petersen; Joseph DeRisi; Richard Michelmore; Diane Havlir

doi:10.1093/ofid/ofac135

Viral Load Among Vaccinated and Unvaccinated, Asymptomatic and Symptomatic Persons Infected With the SARS-CoV-2 Delta Variant

Open Forum Infect Dis. 2022 Mar 17;9(5):ofac135. doi: 10.1093/ofid/ofac135. eCollection 2022 May.

Authors

Charlotte B Acharya¹, John Schrom², Anthea M Mitchell³, David A Coil¹, Carina Marquez^{2

4}, Susana Rojas², Chung Yu Wang³, Jamin Liu⁵, Genay Pilarowski^{2

6}, Leslie Solis¹, Elizabeth Georgian¹, Sheri Belafsky⁷, Maya Petersen^{2

8}, Joseph DeRisi³, Richard Michelmore¹, Diane Havlir^{2

4}

Affiliations

¹ Genome Center, University of California, Davis, Davis, California, USA.
² Unidos en Salud, San Francisco, California, USA.
³ Chan Zuckerberg Biohub and Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, California, USA.
⁴ Division of HIV, Infectious Disease and Global Medicine, Department of Medicine, University of California, San Francisco, San Francisco, California, USA.
⁵ Joint UCB/UCSF Bioengineering Program, University of California, Berkeley, and University of California, San Francisco, San Francisco, California, USA.
⁶ The Public Health Company, Oakland, California, USA.
⁷ Department of Public Health Sciences, University of California, Davis, Davis, California, USA.
⁸ School of Public Health, University of California, Berkeley, Berkeley, California, USA.

Abstract

We found no significant difference in cycle threshold values between vaccinated and unvaccinated persons infected with severe acute respiratory syndrome coronavirus 2 Delta, overall or stratified by symptoms. Given the substantial proportion of asymptomatic vaccine breakthrough cases with high viral levels, interventions, including masking and testing, should be considered in settings with elevated coronavirus disease 2019 transmission.

Keywords: 19; COVID; Ct value; Delta variant; SARS-CoV-2; asymptomatic testing.