Vaccination Against SARS-CoV-2 Is Associated With a Lower Viral Load and Likelihood of Systemic Symptoms

Carolyn T Bramante; Jennifer L Proper; David R Boulware; Amy B Karger; Thomas Murray; Via Rao; Aubrey Hagen; Christopher J Tignanelli; Michael Puskarich; Ken Cohen; David M Liebovitz; Nichole R Klatt; Courtney Broedlow; Katrina M Hartman; Jacinda Nicklas; Sherehan Ibrahim; Adnin Zaman; Hanna Saveraid; Hrishikesh Belani; Nicholas Ingraham; Grace Christensen; Lianne Siegel; Nancy E Sherwood; Regina Fricton; Sam Lee; David J Odde; John B Buse; Jared D Huling

doi:10.1093/ofid/ofac066

Vaccination Against SARS-CoV-2 Is Associated With a Lower Viral Load and Likelihood of Systemic Symptoms

Open Forum Infect Dis. 2022 Feb 20;9(5):ofac066. doi: 10.1093/ofid/ofac066. eCollection 2022 May.

Authors

Carolyn T Bramante¹, Jennifer L Proper², David R Boulware³, Amy B Karger⁴, Thomas Murray², Via Rao¹, Aubrey Hagen¹, Christopher J Tignanelli⁵, Michael Puskarich⁶, Ken Cohen⁷, David M Liebovitz⁸, Nichole R Klatt⁵, Courtney Broedlow⁵, Katrina M Hartman¹, Jacinda Nicklas⁹, Sherehan Ibrahim¹, Adnin Zaman⁹, Hanna Saveraid¹, Hrishikesh Belani¹⁰, Nicholas Ingraham¹¹, Grace Christensen¹, Lianne Siegel², Nancy E Sherwood¹², Regina Fricton⁸, Sam Lee⁸, David J Odde¹³, John B Buse¹⁴, Jared D Huling²

Affiliations

¹ General Internal Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
² Biostatistics, University of Minnesota School of Public Health, Minneapolis, Minnesota, USA.
³ Infectious Diseases & International Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
⁴ Laboratory Medicine & Pathology, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
⁵ Surgery, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
⁶ Department of Emergency Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
⁷ Optum Center for Research and Innovation, Optum, Minnetonka, Minnesota, USA.
⁸ General Internal Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
⁹ General Internal Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA.
¹⁰ Primary Care, Olive View - UCLA Medical Center, Los Angeles, California, USA.
¹¹ Pulmonary, Allergy, Critical Care & Sleep Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
¹² Epidemiology, University of Minnesota School of Public Health, Minneapolis, Minnesota, USA.
¹³ Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
¹⁴ Endocrinology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.

Abstract

Background: Data conflict on whether vaccination decreases severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load. The objective of this analysis was to compare baseline viral load and symptoms between vaccinated and unvaccinated adults enrolled in a randomized trial of outpatient coronavirus disease 2019 (COVID-19) treatment.

Methods: Baseline data from the first 433 sequential participants enrolling into the COVID-OUT trial were analyzed. Adults aged 30-85 with a body mass index (BMI) ≥25 kg/m² were eligible within 3 days of a positive SARS-CoV-2 test and <7 days of symptoms. Log₁₀ polymerase chain reaction viral loads were normalized to human RNase P by vaccination status, by time from vaccination, and by symptoms.

Results: Two hundred seventy-four participants with known vaccination status contributed optional nasal swabs for viral load measurement: median age, 46 years; median (interquartile range) BMI 31.2 (27.4-36.4) kg/m². Overall, 159 (58%) were women, and 217 (80%) were White. The mean relative log₁₀ viral load for those vaccinated <6 months from the date of enrollment was 0.11 (95% CI, -0.48 to 0.71), which was significantly lower than the unvaccinated group (P = .01). Those vaccinated ≥6 months before enrollment did not differ from the unvaccinated with respect to viral load (mean, 0.99; 95% CI, -0.41 to 2.40; P = .85). The vaccinated group had fewer moderate/severe symptoms of subjective fever, chills, myalgias, nausea, and diarrhea (all P < .05).

Conclusions: These data suggest that vaccination within 6 months of infection is associated with a lower viral load, and vaccination was associated with a lower likelihood of having systemic symptoms.

Keywords: SARS-CoV-2; symptoms; vaccines; viral load.

Abstract

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