Emerging Infectious Diseases (Jul 2023)

Effect of Norovirus Inoculum Dose on Virus Kinetics, Shedding, and Symptoms

  • Yang Ge,
  • W. Zane Billings,
  • Antone Opekun,
  • Mary Estes,
  • David Graham,
  • Juan Leon,
  • Katia Koelle,
  • Ye Shen,
  • Robert Atmar,
  • Benjamin Lopman,
  • Andreas Handel

DOI
https://doi.org/10.3201/eid2907.230117
Journal volume & issue
Vol. 29, no. 7
pp. 1349 – 1356

Abstract

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The effect of norovirus dose on outcomes such as virus shedding and symptoms after initial infection is not well understood. We performed a secondary analysis of a human challenge study by using Bayesian mixed-effects models. As the dose increased from 4.8 to 4,800 reverse transcription PCR units, the total amount of shed virus in feces increased from 4.5 × 1011 to 3.4 × 1012 genomic equivalent copies; in vomit, virus increased from 6.4 × 105 to 3.0 × 107 genomic equivalent copies. Onset time of viral shedding in feces decreased from 1.4 to 0.8 days, and time of peak viral shedding decreased from 2.3 to 1.5 days. Time to symptom onset decreased from 1.5 to 0.8 days. One type of symptom score increased. An increase in norovirus dose was associated with more rapid shedding and symptom onset and possibly increased severity. However, the effect on virus load and shedding was inconclusive.

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