COVID-19 Evidence Alerts
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Prognosis Yan D, Zhang X, Chen C, et al. Characteristics of Viral Shedding Time in SARS-CoV-2 Infections: A Systematic Review and Meta-Analysis. Front Public Health. 2021 Mar 19;9:652842. doi: 10.3389/fpubh.2021.652842. eCollection 2021.

Background: The viral shedding time (VST) of SARS-CoV-2 mainly determines its transmission and duration of infectiousness. However, it was heterogeneous in the existing studies. Here, we performed a meta-analysis to comprehensively summarize the VST of SARS-CoV-2. Methods: We searched PubMed, Web of Science, MedRxiv, BioRxiv, CNKI, CSTJ, and Wanfang up to October 25, 2020, for studies that reported VSTs of SARS-CoV-2. Pooled estimates and 95% CIs for the VSTs were calculated using log-transformed data. The VSTs in SARS-CoV-2 infections based on different demographic and clinical characteristics, treatments and specimens were stratified by subgroup analysis. Results: A total of 35 studies involving 3,385 participants met the inclusion criteria. The pooled mean VST was 16.8 days (95% CI: 14.8-19.4, I2 = 99.56%) in SARS-CoV-2 infections. The VST was significantly longer in symptomatic infections (19.7 days, 95% CI: 17.2-22.7, I2 = 99.34%) than in asymptomatic infections (10.9 days, 95% CI: 8.3-14.3, I2 = 98.89%) (P < 0.05). The VST was 23.2 days (95% CI: 19.0-28.4, I2 = 99.24%) in adults, which was significantly longer than that in children (9.9 days, 95% CI: 8.1-12.2, I2 = 85.74%) (P < 0.05). The VST was significantly longer in persons with chronic diseases (24.2 days, 95% CI: 19.2-30.2, I2 = 84.07%) than in those without chronic diseases (11.5 days, 95% CI: 5.3-25.0, I2 = 82.11%) (P < 0.05). Persons receiving corticosteroid treatment (28.3 days, 95% CI: 25.6-31.2, I2 = 0.00%) had a longer VST than those without corticosteroid treatment (16.2 days, 95% CI: 11.5-22.5, I2 = 92.27%) (P = 0.06). The VST was significantly longer in stool specimens (30.3 days, 95% CI: 23.1-39.2, I2 = 92.09%) than in respiratory tract specimens (17.5 days, 95% CI: 14.9-20.6, I2 = 99.67%) (P < 0.05). Conclusions: A longer VST was found in symptomatic infections, infected adults, persons with chronic diseases, and stool specimens.

Discipline / Specialty Area Score
General Internal Medicine-Primary Care(US)
Hospital Doctor/Hospitalists
Internal Medicine
Family Medicine (FM)/General Practice (GP)
Intensivist/Critical Care
Pediatrics (General)
Pediatric Hospital Medicine
Pediatric Emergency Medicine
Public Health
Emergency Medicine
Infectious Disease
Comments from MORE raters

Emergency Medicine rater

A very timely and useful article on viral-shedding time for SARS. This is important for EM physicians to help patients understand infectious times and isolation for discharge planning. This may also help when variants become an issue as well.

General Internal Medicine-Primary Care(US) rater

This is important to help institutions with guidelines for isolation, return to work, and repeat testing for "family members," etc. Earlier in the pandemic, every LTC facility and NH was struggling to make up rules for family visitations, etc. Some were asking for 2 negative tests within 48-72 hours to allow visitation to rehab facilities where the spouse was recovering from ICU care. It made no sense that positive tests 4-6 weeks out of infection meant no visitation, as clinically the VL would be low. This article may help to develop more appropriate guidelines.

Infectious Disease rater

I am concerned that they included very small studies and also non-peer reviewed studies. It's curious that so many of the included studies seemed to originate in Asia. I worry about generalizability as well. There are too many red flags for study quality here.

Intensivist/Critical Care rater

The clinical implication of these findings is not clear. If VST translates into infectiousness, the implications would be disquieting.

Intensivist/Critical Care rater

Very interesting paper describing viral spreading time. This spreading time varies with multiples factors, including age, chronic disease, steroid use, and symptoms. This is relevant information to be considered when we have to determine the duration of quarantine.

Internal Medicine rater

Uncertain how this should be used clinically.

Pediatric Emergency Medicine rater

Hopefully, the shed time will not gradually increase during the continued rapacity of the virus.

Pediatric Hospital Medicine rater

Important data in determining the infectiousness of COVID depending on source and severity of illness.

Pediatrics (General) rater

Important information for managing patients affected by COVID-19.

Pediatrics (General) rater

A good meta-analysis of viral shedding time.

Public Health rater

Results are interesting and useful, but in interpretation it 'd be considered that RT PCR is not a viral culture, and does not allow determination of whether the virus is viable and transmissible. Accordingly, a positive test does not necessarily means that the patient can transmit the virus, and further studies are needed to verify this hypothesis (see: Liotti et al, JAMA 2021).