Anal Swab in COVID-19 Patients

In 2020, a new type of coronavirus (SARS-CoV-2) whose disease is called Coronavirus disease 2019 (COVID-19) has been reported. This virus was first discovered in Wuhan, China and has infected 90,308 people per March 2, 2020. As of the end of October 2020, more than 40 million people have been infected, with the death toll reaching 1,150,000 worldwide. Apart from respiratory tract infections, patients infected with this virus may exhibit other symptoms, such as diarrhea, abdominal pain, nausea, or vomiting. This means that the virus can be found in feces and anus, hence the anal swab can be used as a diagnostic tool for COVID-19 infection. The results of the specimen test show that the sensitivity of the nasopharyngeal swab positive detection rate is the highest and remains the gold standard for diagnosis. This sensitivity can also be influenced by the course of the disease that can infect the gastrointestinal tract so that anal PCR is performed for the diagnosis to detect the COVID-19 virus in patients.

Evaluation of the presence of SARS-CoV-2 in vaginal and anal swabs of women with omicron variants of SARS-CoV-2 infection.

Objectives: The study aimed to determine whether SARS-CoV-2 Omicron variant could be detected in the vaginal fluid and anal swabs of reproductive-aged and postmenopausal women infected with SARS-CoV-2 Omicron variant. Methods: Included in this study were 63 women who were laboratory confirmed as having SARS-CoV-2 Omicron variant infection and admitted to the responsible ward of Daping Hospital of at the National Exhibition and Convention Center(Shanghai) Makeshift Hospital from May 1-24, 2022.From them, vaginal and anal swabs were obtained with informed consent. The demographic and baseline clinical characteristics and the swab test results were analyzed. Results: The 63 included patients ranged in age from 18 to 72 years with a median of 47.71 ± 15.21 years. Of them, 38 women (60.3%) were in their reproductive years. Most of the participants (77.8%) were healthy without significant underlying diseases. Fourteen patients (22.2%) had asymptomatic infection and the remaining 49 (77.8%) had mild infection. The upper respiratory tract symptoms including cough (40/63.5%) and sore throat (18/28.6%)were the most common clinical manifestations of these mildly infected patients. Only 5 patients (7.8%) had gastrointestinal (GI) symptoms, including simple diarrhea in 4 patients, and diarrhea with vomiting in one patient. Pharyngeal,vaginal and anal swabs were collected simultaneously from all 63 patients 8-16 (mean 11.25 ± 2.23) days after SARS-Cov-2 Omicron variant infection. The vaginal swabs were negative for SARS-CoV-2 in all 63 patients, and the anal swabs were positive in 4 patients (6.5%). The overall median hospitalization duration was 16.73 ± 3.16 days. Conclusion: The results of the present study suggest that there is a low possibility of SARS-Cov-2 Omicron variant transmission via the digestive tract and vaginal fluid. The correlation between the GI symptoms and the presence of viral RNA in anal swabs is uncertain.

Anal Swab in COVID-19 Patients.

In 2020, a new type of coronavirus (SARS-CoV-2) whose disease is called Coronavirus disease 2019 (COVID-19) has been reported. This virus was first discovered in Wuhan, China and has infected 90,308 people per March 2, 2020. As of the end of October 2020, more than 40 million people have been infected, with the death toll reaching 1,150,000 worldwide. Apart from respiratory tract infections, patients infected with this virus may exhibit other symptoms, such as diarrhea, abdominal pain, nausea, or vomiting. This means that the virus can be found in feces and anus, hence the anal swab can be used as a diagnostic tool for COVID-19 infection. The results of the specimen test show that the sensitivity of the nasopharyngeal swab positive detection rate is the highest and remains the gold standard for diagnosis. This sensitivity can also be influenced by the course of the disease that can infect the gastrointestinal tract so that anal PCR is performed for the diagnosis to detect the COVID-19 virus in patients.

Possible intraindividual evolution of SARS-CoV-2 in nasopharyngeal and anal swab in an octogenarian: a case report.

Introduction: COVID-19 is an emerging infectious disease that remains to be further investigated. Case report: Here, we describe a case of COVID-19 in an octogenarian woman with comorbidities who slowly recovered during hospitalization, but died due to sudden cardiac death after 2 weeks of hospitalization. Her nasopharyngeal and anal swabs returned positive for SARS-CoV-2 by RT-PCR on day 7 of hospitalization. The NGS showed possible intraindividual evolution of virus. The sample from the nasopharyngeal swab yielded a B.1470 variant classified as clade GH. This variant showed mutation in the spike gene D614G; N gene; NS3 gene; NSP2 gene and NSP12 gene. The sample from the anal swab showed similar mutation but with additional point mutation in spike gene S12F and was classified as B.1.465 variant. Conclusions: The possibility of the gastrointestinal tract that served as reservoir for virus mutation accumulation should also be considered and the potential impact of viral fecal transmission in the environment should be further investigated.

COVID-19 in the gut and liver

Coronavirus disease 2019 (COVID-19) is known to result in gastrointestinal symptoms and liver damage. Consideration needs to be given to COVID-19 as a potential cause of new-onset gastrointestinal symptoms. Awareness of special issues affecting patients with chronic gastrointestinal and liver diseases in a pandemic is important. © 2021 Medicine Today Pty Ltd. All rights reserved.

Value of anal swabs for SARS-COV-2 detection: a literature review.

Facing the unprecedented global public health crisis caused by coronavirus disease 2019 (COVID-19), nucleic acid tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are the gold standard for diagnosing COVID-19. The asymptomatic carriers were not suspected of playing a significant role in the ongoing pandemic, and universal nucleic acid screening in close contacts of confirmed cases and asymptomatic carriers has been carried out in many medium- and high-risk areas for the spread of the virus. Recently, anal swabs for key population screening have been shown to not only reduce missed diagnoses but also facilitate the traceability of infectious sources. As a specimen for the detection of viruses, the goal of this paper is to briefly review the transmission route of SARS-CoV-2 and the necessity of using anal swabs for SARS-CoV-2 screening to minimize transmission and a threat to other people with COVID-19.

Association between detectable SARS-COV-2 RNA in anal swabs and disease severity in patients with coronavirus disease 2019.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was found in the intestines and feces, but its clinical significance is not completely clear. We aim to characterize the longitudinal test results of SARS-CoV-2 RNA in anal swabs and to explore the association with disease severity. METHODS: We included laboratory-confirmed coronavirus disease 2019 (COVID-19) patients, who were hospitalized in Guangzhou Eighth People's Hospital and excluded those who had not received anal swabs for SARS-COV-2 RNA testing. Epidemiological, clinical, and laboratory data were obtained. Throat swabs and anal swabs were collected periodically for SARS-COV-2 RNA detection. RESULTS: Two hundred and seventeen eligible patients (median aged 50 years, 50.2% were females) were analyzed. 21.2% (46/217) of the patients were detected with SARS-CoV-2 RNA in anal swabs. The duration of viral RNA was longer, but the viral load was lower in anal swabs than throat swabs in the early stage of the disease. During a median follow-up of 20 days, 30 (13.8%) patients were admitted to the intensive care unit (ICU) for high-flow nasal cannula or higher-level oxygen support measures to correct hypoxemia. Detectable viral RNA in anal swabs (adjusted hazard ratio [aHR], 2.50; 95% confidence interval [CI], 1.20-5.24), increased C-reactive protein (aHR, 3.14; 95% CI, 1.35-7.32) and lymphocytopenia (aHR, 3.12; 95% CI, 1.46-6.67) were independently associated with ICU admission. The cumulative incidence of ICU admission was higher among patients with detectable viral RNA in anal swabs (26.3% vs 10.7%, P = .006). CONCLUSION: Detectable SARS-CoV-2 RNA in the digestive tract was a potential warning indicator of severe disease.

Coronavirus (SARS-CoV-2) in gastroenterology and its current epidemiological situation: An updated review until January 2021.

Coronaviruses are positive-sense single-strand RNA viruses that infect amphibians, birds, and mammals. Coronavirus Disease 2019 (COVID-19) has become a major health problem caused by one of the coronaviruses called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has spread fast throughout the globe since its first identification in Wuhan, China, in December 2019. Although COVID-19 is principally defined by its respiratory symptoms, it is now clear that the virus can also affect the digestive system causing gastrointestinal (GI) symptoms like diarrhea, loss of appetite, nausea/vomiting, and abdominal pain as a major complaint. GI symptoms could be the initial signs of preceding respiratory signs, carrying a potential for slowed investigation and raised disease transmission opportunities. Various studies recognized the COVID-19 RNA in stool specimens of infected patients, and its viral receptor angiotensin-converting enzyme-2 (ACE-2) is highly expressed in GI epithelial cells. Many cases were reported negative using nasopharyngeal/oropharyngeal swabs and finally, SARS-CoV-2 RNA was detected in their anal/rectal swabs and stool specimens. These suggest that COVID-19 can actively infect and replicate in the GI tract. In this review, we elaborate on the close relationship between SARS-CoV-2 and the digestive system, focusing on the current status in the field of COVID-19 in gastroenterology, liver injury, endoscopy, inflammatory bowel disease, imaging, and the potential underlying mechanisms with illustrating the current epidemiological status regarding this pandemic.

Higher viral loads in asymptomatic COVID-19 patients might be the invisible part of the iceberg.

PURPOSE: SARS-CoV-2 virus dynamics in different hosts and different samples and their relationship with disease severity have not been clearly revealed. The aim of this study is to evaluate the viral loads of 6 different sample types (nasopharyngeal/oropharyngeal combined, oral cavity, saliva, rectal, urine, and blood) of patients with different ages and clinics, to reveal the relationship between disease course and SARS-CoV-2 viral load, and differences in viral loads of asymptomatic and symptomatic patients. METHODS: Nasopharyngeal/oropharyngeal, oral cavity, saliva, rectal, urine, and blood samples are collected from patients who were hospitalized with diagnosis of COVID-19 on admission. Laboratory analysis were carried out at Public Health Institute of Turkey Virology Reference and Research Laboratory. RESULTS: A total of 360 samples from 60 patients were obtained on admission. Fifteen (25%) of the patients were asymptomatic while 45 (75%) were symptomatic. A significant difference was found between mean ages of asymptomatic vs symptomatic patients (26.4 and 36.4, respectively, p = 0.0248). No PCR positivity were found in blood. Only one asymptomatic patient had positive PCR result for urine sample. Viral loads of asymptomatic patients were found to be significantly higher (p = 0.0141) when compared with symptomatic patients. Viral load had a significant negative trend with increasing age. A significant decrease in viral load was observed with increasing disease severity. CONCLUSION: In conclusion, this study demonstrates that asymptomatic patients have higher SARSCoV-2 viral loads than symptomatic patients and unlike in the few study in the literature, a significant decrease in viral load of nasopharyngeal/oropharyngeal samples was observed with increasing disease severity. Factors associated with poor prognosis are found to be significantly correlated with low viral load.

Comparison of SARS-CoV-2 RT-PCR on a high-throughput molecular diagnostic platform and the cobas SARS-CoV-2 test for the diagnostic of COVID-19 on various clinical samples.

OBJECTIVES: In order to cope with the rapid spread of the COVID-19 pandemic, we introduced on our in-house high-throughput molecular diagnostic platform (MDx Platform) a real-time reverse transcriptase PCR (RT-PCR) to detect the SARS-CoV-2 from any clinical specimens. The aim of this study was to compare the RT-PCR results obtain with the MDx Platform and the commercial assay cobas SARS-CoV-2 (Roche) on nasopharyngeal swab and other clinical specimens including sputum, bronchial aspirate, bronchoalveolar lavage and anal swabs. METHODS: Samples received in our laboratory from patients suspected of COVID-19 (n = 262) were tested in parallel with our MDx platform SARS-CoV-2 PCR and with the cobas SARS-CoV-2 test. RESULTS: The overall agreement between the two tests for all samples tested was 99.24% (260/262), which corresponded to agreements of 100% (178/178) on nasopharyngeal swabs, 95.45% (42/44) on lower respiratory tract specimen with discordant resultS obtained for very high cycle threshold (Ct) value and 100% (40/40) on anorectal swabs. The Ct values for nasopharyngeal swabs displayed an excellent correlation (R2 > 96%) between both tests. CONCLUSIONS: The high agreements between the cobas SARS-CoV-2 test and the MDx platform supports the use of both methods for the diagnostic of COVID-19 on various clinical samples. Very few discrepant results may occur at very low viral load.

Clinical and imaging findings of discharged patients with SARS-CoV-2 positive anal swab samples: a descriptive study.

BACKGROUND: To explore the clinical features and CT findings of clinically cured coronavirus disease 2019 (COVID-19) patients with viral RNA positive anal swab results after discharge. METHODS: Forty-two patients with COVID-19 who were admitted to Yongzhou Central Hospital, Hunan, China, between January 20, 2020, and March 2, 2020, were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using anal swab viral RT-PCR. In this report, we present the clinical characteristics and chest CT features of six patients with positive anal swab results and compare the clinical, laboratory, and CT findings between the positive and negative groups. RESULTS: The anal swab positivity rate for SARS-CoV-2 RNA in discharged patients was 14.3% (6/42). All six patients were male. In the positive group, 40% of the patients (2/5) had a positive stool occult blood test (OBT), but none had diarrhea. The median duration of fever and major symptoms (except fever) in the positive patients was shorter than that of the negative patients (1 day vs. 6 days, 4.5 days vs. 10.5 days, respectively). The incidence of asymptomatic cases in the positive group (33.3%) was also higher than that of the negative group (5.6%). There were no significant differences in the CT manifestation or evolution of the pulmonary lesions between the two groups. CONCLUSION: In our case series, patients with viral RNA positive anal swabs did not exhibit gastrointestinal symptoms, and their main symptoms disappeared early. They had similar CT features to the negative patients, which may be easier to be ignored. A positive OBT may indicate gastrointestinal damage caused by SARS-CoV-2 infection.

Systematic review with meta-analysis: SARS-CoV-2 stool testing and the potential for faecal-oral transmission.

BACKGROUND: Since the start of the COVID-19 pandemic, there have been many scientific reports regarding gastrointestinal manifestations. Several reports indicate the possibility of viral shedding via faeces and the possibility of faecal-oral transmission. AIMS: To critically assess the clinical relevance of testing stool samples and anal swabs and provide an overview of the potential faecal-oral transmission of SARS-CoV-2. METHODS: A systematic literature search with MeSH terms was performed, scrutinising the Embase database, Google scholar, MEDLINE database through PubMed and The Cochrane Library, including articles from December 2019 until July 7 2020. Data were subsequently analysed with descriptive statistics. RESULTS: Ninety-five studies were included in the qualitative analysis. 934/2149 (43%) patients tested positive for SARS-CoV-2 in stool samples or anal swabs, with positive test results up to 70 days after symptom onset. A meta-analysis executed with studies of at least 10 patients revealed a pooled positive proportion of 51.8% (95% CI 43.8 - 59.7%). Positive faecal samples of 282/443 patients (64%) remained positive for SARS-CoV-2 for a mean of 12.5 days, up to 33 days maximum, after respiratory samples became negative for SARS-CoV-2. Viable SARS-CoV-2 was found in 6/17 (35%) patients in whom this was specifically investigated. CONCLUSIONS: Viral shedding of SARS-CoV-2 in stool samples occurs in a substantial proportion of patients, making faecal-oral transmission plausible. Furthermore, detection in stool samples or anal swabs can persist long after negative respiratory testing. Therefore, stool sample or anal swab testing should be (re)considered in relation to decisions for isolating or discharging a patient.

An infant with a mild SARS-CoV-2 infection detected only by anal swabs: a case report.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China and has spread rapidly worldwide. We present a mild SARS-CoV-2 infection in a baby with non-productive cough and normal chest computed tomography, in whom only anal swabs tested positive by real-time PCR testing for SARS-CoV-2. She was given atomization inhalation therapy with recombinant human interferon alfa-1b for 10 days. Her anal swabs remained positive for eight days, whereas her throat swabs were persistently negative by real-time PCR testing. Mild and asymptomatic cases, especially in children, might present with PCR negative pharyngeal/nasal swabs and PCR positive anal swabs. Those patients are potential sources of infection via fecal-oral transmission for COVID-19.

Anal swab findings in an infant with COVID-19.

INTRODUCTION: The transmission pathways of coronavirus disease 2019 (COVID-19) remain not completely clear. In this case study the test for the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in pharyngeal swab and anal swab were compared. CASE PRESENTATION: A 3-month-old girl was admitted to our hospital with COVID-19. Her parents had both been diagnosed with COVID-19. The results of pharyngeal swab and anal swab of the little girl were recorded and compared during the course of the disease. The oropharyngeal specimen showed negative result for SARS-CoV-2 on the 14th day after onset of the illness. However, the anal swab was still positive for SARS-CoV-2 on the 28th day after the onset of the illness. CONCLUSION: The possibility of fecal-oral transmission of COVID-19 should be assessed. Personal hygiene during home quarantine merits considerable attention.

Detectable 2019-nCoV viral RNA in blood is a strong indicator for the further clinical severity.

The novel coronavirus (2019-nCoV) infection caused pneumonia. we retrospectively analyzed the virus presence in the pharyngeal swab, blood, and the anal swab detected by real-time PCR in the clinical lab. Unexpectedly, the 2109-nCoV RNA was readily detected in the blood (6 of 57 patients) and the anal swabs (11 of 28 patients). Importantly, all of the 6 patients with detectable viral RNA in the blood cohort progressed to severe symptom stage, indicating a strong correlation of serum viral RNA with the disease severity (p-value = 0.0001). Meanwhile, 8 of the 11 patients with annal swab virus-positive was in severe clinical stage. However, the concentration of viral RNA in the anal swab (Ct value = 24 + 39) was higher than in the blood (Ct value = 34 + 39) from patient 2, suggesting that the virus might replicate in the digestive tract. Altogether, our results confirmed the presence of virus RNA in extra-pulmonary sites.