Insight into the reason of prolonged viral RNA shedding in patients with COVID-19 infection
Authors: Marco Bongiovanni, Francesco Bini, Giuseppe Giuliani, Luigi Gianturco
Journal: Journal of Infection (2021)

•Older age is the most important predictor of prolonged viral shedding in patients with SARS-CoV-2 infection.•Male gender was a predictor of prolonged viral shedding only at univariate analysis.•Disease severity (considering hospitalization and deaths) was not associated with a prolonged viral shedding. Severe acute respiratory syndrome coronavirus (SARS-CoV-2), a novel RNA coronavirus from the same family as SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), was identified in early January 2020 as the cause of a pneumonia epidemic affecting the city of Wuhan, the capital of Hubei province, from where it rapidly spread across China.1Chan J.F.-.W. Yuan S. Kok K.-.H. To K.K. Chu H. Yang J. et al.A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster.Lancet. 2020; 395: 514-523Abstract Full Text Full Text PDF PubMed Scopus (6145) Google Scholar,2Wang D. Hu B. Hu C. et al.Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected-pneumonia in Wuhan, China.JAMA. 2020; 323: 1061-1069Crossref PubMed Scopus (16024) Google Scholar From China, infection rapidly reached Europe and USA, with the number of new cases currently increasing every day.3Rothe C. Schunk M. Sothmann P. Bretzel G. Froeschl G. Wallrauch C. et al.Transmission of SARS-CoV-2 infection from an asymptomatic contact in Germany.N Engl J Med. 2020; 382: 970-971Crossref PubMed Scopus (2797) Google Scholar,4Holshue M.L. DeBolt C. Lindquist S. Lofy K.H. Wiesman J. Bruce H. et al.First case of 2019 novel coronavirus in the United States.N Engl J Med. 2020; 382: 929-936Crossref PubMed Scopus (4252) Google Scholar The World Health Organization declared the coronavirus diseases 2019 (COVID-19) as a pandemic due to the widespread infectivity and high contagion rate.5Mahase E. Covid-19: WHO declares pandemic because of "alarming levels" of spread, severity, and inaction.BMJ. 2020; 368: m1036Crossref PubMed Scopus (438) Google Scholar According to the WHO's guidelines on clinical management, a patient can be discharged from hospital after two consecutive negative real-time reverse-transcriptase polymerase-chain-reaction (RT-PCR) tests at nasopharyngeal swabs at least 24 h apart in a clinically recovered patient (https://ecdc.europa.eu/en/publications-data/covid-19-guidance-discharge-and-ending-isolation). The pattern of SARS-CoV-2 RNA shedding during the course of COVID-19 infection has not been well characterized to date. Several reports assessed the possible recurrence of COVID-19 infection,6Bongiovanni M. Vignati M. Giuliani G. Manes G. Arienti S. Pelucchi L. et al.The dilemma of COVID-19 recurrence after clinical recovery.J Infect. 2020; https://doi.org/10.1016/j.jinf.2020.08.019Abstract Full Text Full Text PDF Scopus (22) Google Scholar,7Batisse D. Benech N. Botelho-Nevers E. Bouiller K. Collarino R. Conrad A. et al.Clinical recurrences of COVID-19 symptoms after recovery: viral relapse, reinfection or inflammation rebound?.J Infect. 2020; (Jun 30 S0163-4453(20)30454-0)Google Scholar but little information is known about the prolonged persistence of viral RNA shedding; in particular, two recent, small, retrospective studies found that male sex, delayed admission to hospital after illness onset and disease severity were all associated with a prolonged SARS-CoV-2 RNA shedding.8Xu K. Chen Y. Yuan J. Yi P. Ding C. Wu W. et al.Factors associated with prolonged viral RNA shedding in patients with COVID-19.Clin Infect Dis. 2020; 71: 799-806Crossref PubMed Scopus (354) Google Scholar,9Shi D. Wu W. Wang Q. Xu K. Xie J. Wu J. et al.Clinical characteristics and factors associated with long-term viral excretion in patients with severe acute respiratory syndrome coronavirus 2 infection: a single center 28-day study.J Infect Dis. 2020; 222: 910-918Crossref PubMed Scopus (51) Google Scholar Recently, a paper by Fang et al.10Fang Z. Zhang Y. Hang C. Ai J. Li S. Zhang W. Comparison of viral shedding time of SARS-CoV-2 of different samples in ICU and non-ICU patients.J Infect. 2020; 81: 147-148Scopus (108) Google Scholar compared the time of viral shedding of SARS-CoV-2 in patients hospitalized in intensive care unit (ICU) or not; in particular, they found that the time of viral shedding of blood, saliva and nasal samples was longer in ICU-patients compared to others, and exceeded two weeks in all the patients included. The authors suggest that these differences might be correlated with viral load, severity and invasive operations related to ICU hospitalization. In the present paper we evaluated the factors associated with a prolonged SARS-CoV-2 RNA shedding in a large population of patients followed-up at ASST Rhodense from March to September 2020. In this analysis, we included 681 subjects with a confirmed COVID-19 infection; patients were diagnosed by a nasopharyngeal swab between March 2010 and September 2010, and had a follow-up of at least 8 weeks. Population was divided into three groups according to the time needed to swab negativization (defined as two consecutive negative nasopharyngeal swabs repeated after 24–48 h from each other). Group A included 284 patients who got negative < 3 weeks ("early" negativization); Group B included 225 patients who got negative after 3–6 weeks ("medium" negativization); Group C included 172 patients who got negative > 6 weeks ("late" negativization). Clinical and demographical features were collected in the entire population, as were data on disease severity (need of hospitalization or not) and death. Continuous variables were expressed as mean values and standard deviations (SD) or as median values and interquartile ranges (IQR) according to variable skewness. Non-continuous variables were described as percentages. Normal distribution was tested using the Kolmogorov–Smirnov test and statistical parametric techniques were applied. The in-between groups comparison was performed by one-way analysis of variance ANOVA and post-hoc analyses using Scheffè test were performed when the main effect was significant. All data analysis was performed using the MedCalc software © (Ostend, Belgium, version 12.7.0) and significance was conventionally set at 5% (p < 0.05). First of all, we assessed normal distribution of our sample and also identified little number of possible outliers Then, we preliminary divided total number of study population in 3 groups according to time to negativization. Table 1 summarized clinical and demographic characteristics of the population studied, according to the 3 groups considered. At univariate analysis, male gender was associated with a prolonged time to recovery (p < 0.05). Patients who recovered earlier were younger than others (mean age: Group "early" negativization 50.5 years, Group "medium" negativization 57 years, Group "late" negativization 65.8 years, p < 0.05). The percentage of hospitalized patients was higher, though not statistically significant among Group "late" negativization (75.6%) compared to others (Group "early" 41.4%, Group "medium" 48.4%, p = 0.08), as was the percentage of deaths (8.1% vs 5.3% Group "medium2 and 1.1% Group "early", p = 0.09). Subsequently, a stepwise multiple regression (backward model) was used to analyze main underlying relationship between study's parameters; with this specific analysis, we found only one strong relationship between time to negativization and age. Fig. 1 shows the correlation between older age and time to negativization evaluated by ANOVA statistical analysis.Table 1Demographic and clinical characteristics of the population according to the time to negativization. Group "early": 〈 3 weeks; Group "medium": 3–6 weeks; Group "late": 〉 6 weeks.Group "Early" (n = 284)Group "Medium" (n = 225)Group "Late" (n = 172)pAge, mean (95% CI)50.5 (22–79)57.0 (27–86)65.8 (32–90)< 0.05Male, n (%)208 (53.1)105 (46.7)75 (43.6)< 0.05Days to recovery, median (95% CI)17 (9–21)29 (22–41)53 (43–111)< 0.01Hospitalization, n (%)118 (41.5)109 (48.4)139 (75.6)0.08Deaths, n (%)3 (1.1)12 (5.3)14 (8.1)0.09 Open table in a new tab In this paper we evaluated the factors associated with a prolonged viral shedding in subjects with COVID-19 infection. Current data on this aspect of the disease are lacking and mainly come from Chinese studies that usually include younger patients compared to European studies; moreover, current studies included a smaller population with a limited time of follow-up. In particular, the study by Xu et al.8Xu K. Chen Y. Yuan J. Yi P. Ding C. Wu W. et al.Factors associated with prolonged viral RNA shedding in patients with COVID-19.Clin Infect Dis. 2020; 71: 799-806Crossref PubMed Scopus (354) Google Scholar defined as patients with a prolonged viral shedding those with a time to negativization > 15 days; this issue has been overcome by the observation that most patients included in European cohorts recovered slower.11Bongiovanni M. Marra A.M. De Lauretis A. Bini F. Di Carlo D. Manes G. et al.Natural history of SARS-CoV-2 infection in healthcare workers in Northern Italy.J Hosp Infect. 2020; 106: 709-712Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar In this paper, at multivariate analysis male sex, delayed admission to hospital after symptoms onset and invasive mechanical ventilation were all factors statistically associated with a prolonged viral shedding; older age was associated only at univariate analysis. Similarly, in the study by Shi et al.9Shi D. Wu W. Wang Q. Xu K. Xie J. Wu J. et al.Clinical characteristics and factors associated with long-term viral excretion in patients with severe acute respiratory syndrome coronavirus 2 infection: a single center 28-day study.J Infect Dis. 2020; 222: 910-918Crossref PubMed Scopus (51) Google Scholar male gender, disease severity and lymphocyte count were all predictors of prolonged viral shedding. However, in this study only 99 patients were included and the median follow-up was 28 days; furthermore, the median time of persistent viral shedding was 16 days and only 12 patients had detectable virus up to 30 days after symptoms onset. Also the study by Fang et al.10Fang Z. Zhang Y. Hang C. Ai J. Li S. Zhang W. Comparison of viral shedding time of SARS-CoV-2 of different samples in ICU and non-ICU patients.J Infect. 2020; 81: 147-148Scopus (108) Google Scholar included a limited number of patients (32 patients) that were significantly younger than those included in the present paper. Furthermore, the possible correlation between the prolonged viral shedding and the severity of disease has been observed also in our univariate analysis. The differences among the baseline characteristics of our population and the patients included in the studies by Xu,8Xu K. Chen Y. Yuan J. Yi P. Ding C. Wu W. et al.Factors associated with prolonged viral RNA shedding in patients with COVID-19.Clin Infect Dis. 2020; 71: 799-806Crossref PubMed Scopus (354) Google Scholar by Shi9Shi D. Wu W. Wang Q. Xu K. Xie J. Wu J. et al.Clinical characteristics and factors associated with long-term viral excretion in patients with severe acute respiratory syndrome coronavirus 2 infection: a single center 28-day study.J Infect Dis. 2020; 222: 910-918Crossref PubMed Scopus (51) Google Scholar and by Fang10Fang Z. Zhang Y. Hang C. Ai J. Li S. Zhang W. Comparison of viral shedding time of SARS-CoV-2 of different samples in ICU and non-ICU patients.J Infect. 2020; 81: 147-148Scopus (108) Google Scholar can explain the different results obtained. In our study, though male sex was significantly associated with a prolonged viral shedding at univariate analysis, this finding was non confirmed at the stepwise multiple regression analysis; at this analysis, only age was associated with a prolonged viral shedding. At our knowledge, this is the largest cohort study that evaluated the predictive factors of prolonged viral shedding in patients with COVID-19 infection. In this population, older age showed to be the strongest predictors of prolonged viral shedding. This finding may have a significant impact in the future management of the pandemic, especially in the elderly population. No found. All the authors of the manuscript declare that they do not have any conflict of interest in connection with this paper. Authors are grateful to Dr. Alessandro Maria Marra and Bruno Dino Bodini for their support.