Korean J healthc assoc Infect Control Prev.  2023 Jun;28(1):4-9. 10.14192/kjicp.2023.28.1.4.

Viral Shedding Kinetics in Patients with COVID-19

• Kim SH

• KMID: 2543129
• DOI: http://doi.org/10.14192/kjicp.2023.28.1.4

Abstract

The epidemiologic data revealed that most COVID-19 transmission occurred through contact within 3 to 5 days or less from the symptom onset. However, epidemiologic data are prone to recall and misclassification bias; therefore, laboratory data, including viable viral shedding kinetics, can complement these epidemiologic observations and provide important insight in terms of isolation policy and treatment duration of antiviral therapy. The studies revealed that asymptomatic patients with Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) infection had a similar viral load to symptomatic patients during the early course of the disease but exhibited a more rapid decrease in viral load with the loss of infectivity. Furthermore, symptomatic patients with COVID-19 had high infectivity and high symptom scores during the early course of the disease and gradually lost infectivity and symptom severity. In addition, the studies on the effect of COVID-19 vaccination on viral load kinetics showed that fully vaccinated individuals had a shorter duration of viable viral shedding and a lower secondary attack rate than partially vaccinated or unvaccinated individuals. Furthermore, the more recent variants, such as Omicron had a shorter viable viral shedding time (median 3-5 days from the symptom onset) than the precedent variants, such as Delta (median 8.5 days from the symptom onset). Furthermore, immunocompromised patients with COVID-19 tended to shed viable viruses for a prolonged period of up to a median of 4 weeks from the symptom onset.

Keyword

SARS-CoV-2; COVID-19; Viral shedding kinetics

Figure

• 

  Fig. 1 Electron microscopy image of Coronavirus, which shows a 80 nm particle with spikes within a double membranous vesicle.

• 

  Fig. 2 Detailed viral shedding kinetics of patients with SARS-CoV-2 infection in the peri-symptomatic period. (A) Pre-symptomatic viral shedders (n=6). (B) Symptomatic viral shedders (n=10). The period under quarantine was colored on a blue background. Triangular shapes indicate the PCR results prior to symptom onset. Diamond shapes indicate the PCR results on the day of or after symptom onset. PCR results of the E gene (line), RdRp gene (line), and N gene (line) of SARS-CoV-2 are shown.

• 

  Fig. 3 The schematic viable viral shedding kinetics between non-immunocompromised patients and immunocompromised patients with COVID-19.

Reference

1. Cheng HY, Jian SW, Liu DP, Ng TC, Huang WT, Lin HH. 2020; Contact tracing assessment of COVID-19 transmission dynamics in Taiwan and risk at different exposure periods before and after symptom onset. JAMA Intern Med. 180:1156–63. Erratum in: JAMA Intern Med 2020; 180:1264. DOI: 10.1001/jamainternmed.2020.2020. PMID: 32356867. PMCID: PMC7195694.

2. Ge Y, Martinez L, Sun S, Chen Z, Zhang F, Li F, et al. 2021; COVID-19 transmission dynamics among close contacts of index patients with COVID-19: a population-based cohort study in Zhejiang Province, China. JAMA Intern Med. 181:1343–50. DOI: 10.1001/jamainternmed.2021.4686. PMID: 34424260. PMCID: PMC8383161.

3. Lee S, Kim T, Lee E, Lee C, Kim H, Rhee H, et al. 2020; Clinical course and molecular viral shedding among asymptomatic and symptomatic patients with SARS-CoV-2 infection in a community treatment center in the Republic of Korea. JAMA Intern Med. 180:1447–52. DOI: 10.1001/jamainternmed.2020.3862. PMID: 32780793. PMCID: PMC7411944.

4. Ra SH, Lim JS, Kim GU, Kim MJ, Jung J, Kim SH. 2021; Upper respiratory viral load in asymptomatic individuals and mildly symptomatic patients with SARS-CoV-2 infection. Thorax. 76:61–3. Erratum in: Thorax 2021;76:e3. DOI: 10.1136/thoraxjnl-2020-215042. PMID: 32963115. PMCID: PMC7462047.

5. Bae S, Kim JY, Lim SY, Park H, Cha HH, Kwon JS, et al. 2021; Dynamics of viral shedding and symptoms in patients with asymptomatic or mild COVID-19. Viruses. 13:2133. DOI: 10.3390/v13112133. PMID: 34834940. PMCID: PMC8625453.

6. Hakki S, Zhou J, Jonnerby J, Singanayagam A, Barnett JL, Madon KJ, et al. 2022; Onset and window of SARS-CoV-2 infectiousness and temporal correlation with symptom onset: a prospective, longitudinal, community cohort study. Lancet Respir Med. 10:1061–73. Erratum in: Lancet Respir Med 2022;10:e106. DOI: 10.1016/S2213-2600(22)00226-0. PMID: 35988572. PMCID: PMC9388060.

7. Stankiewicz Karita HC, Dong TQ, Johnston C, Neuzil KM, Paasche-Orlow MK, Kissinger PJ, et al. 2022; Trajectory of viral RNA load among persons with incident SARS-CoV-2 G614 infection (Wuhan strain) in association with COVID-19 symptom onset and severity. JAMA Netw Open. 5:e2142796. DOI: 10.1001/jamanetworkopen.2021.42796. PMID: 35006245. PMCID: PMC8749477.

8. Park S, Lim SY, Kim JY, Park H, Lim JS, Bae S, et al. 2022; Clinical and virological characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.617.2 (Delta) variant: a prospective cohort study. Clin Infect Dis. 75:e27–34. DOI: 10.1093/cid/ciac239. PMID: 35362530. PMCID: PMC9047158.

9. Kang SW, Kim JY, Park H, Lim SY, Kim J, Chang E, et al. 2023; Comparison of secondary attack rate and viable virus shedding between patients with SARS-CoV-2 Delta and Omicron variants: a prospective cohort study. J Med Virol. 95:e28369. Erratum in: J Med Virol 2023;95: e28515. DOI: 10.1002/jmv.28369. PMCID: PMC9877691. PMID: 36458559.

10. Kang SW, Park H, Kim JY, Lim SY, Lee S, Bae JY, et al. 2023; Comparison of the clinical and virological characteristics of SARS-CoV-2 Omicron BA.1/BA.2 and omicron BA.5 variants: a prospective cohort study. J Infect. 86:e148–51. DOI: 10.1016/j.jinf.2023.01.015. PMID: 36669564. PMCID: PMC9846898.

11. Jung J, Kim JY, Park H, Park S, Lim JS, Lim SY, et al. 2022; Transmission and infectious SARS-CoV-2 shedding kinetics in vaccinated and unvaccinated individuals. JAMA Netw Open. 5:e2213606. DOI: 10.1001/jamanetworkopen.2022.13606. PMID: 35608859. PMCID: PMC9131744.

12. Kang SW, Kim JY, Park H, Lim SY, Kim J, Bae S, et al. 2022; Comparison of outward transmission potential between vaccinated and partially vaccinated or unvaccinated individuals with the SARS-CoV-2 delta variant infection. J Infect. 85:e69–71. DOI: 10.1016/j.jinf.2022.06.002. PMID: 35705135. PMCID: PMC9188485.

13. Kissler SM, Fauver JR, Mack C, Tai CG, Breban MI, Watkins AE, et al. 2021; Viral dynamics of SARS-CoV-2 variants in vaccinated and unvaccinated persons. N Engl J Med. 385:2489–91. DOI: 10.1056/NEJMc2102507. PMID: 34941024. PMCID: PMC8693673.

14. Kang SW, Park H, Kim JY, Bae JY, Park MS, Kim SH. 2023; Comparison of culture-competent virus shedding duration of SARS-CoV-2 Omicron variant in regard to vaccination status: a prospective cohort study. Vaccine. 41:2769–72. DOI: 10.1016/j.vaccine.2023.03.044. PMID: 37003909. PMCID: PMC10040344.

15. Centers for Disease Control. 2022. Ending isolation and precautions for people with COVID-19: interim guidance. Centers for Disease Control and Prevention;Atlanta: (Updated on August 31 2022).

16. Kang SW, Kim JW, Kim JY, Lim SY, Jang CY, Chang E, et al. 2023; Characteristics and risk factors of prolonged viable virus shedding in immunocompromised patients with COVID-19: a prospective cohort study. J Infect. 86:412–4. DOI: 10.1016/j.jinf.2023.01.024. PMID: 36682630. PMCID: PMC9852259.

17. Kang SW, Park H, Kim JY, Park S, Lim SY, Lee S, et al. 2022; Clinical scoring system to predict viable viral shedding in patients with COVID-19. J Clin Virol. 157:105319. DOI: 10.1016/j.jcv.2022.105319. PMID: 36223658. PMCID: PMC9529675.

18. Bae S, Park H, Kim JY, Park S, Lim SY, Bae JY, et al. 2022; Daily, self-test rapid antigen test to assess SARS-CoV-2 viability in de-isolation of patients with COVID-19. Front Med (Lausanne). 9:922431. DOI: 10.3389/fmed.2022.922431. PMID: 36341265. PMCID: PMC9627621.