Test-based de-isolation in COVID-19 immunocompromised patients: Cycle threshold value versus SARS-CoV-2 viral culture

Viral cultures, cycle threshold values and viral load estimation for assessing SARS-CoV-2 infectiousness in haematopoietic stem cell and solid organ transplant patients: a systematic review

BACKGROUND

Solid organ and haematopoietic stem cell transplant recipients are more vulnerable to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) than non-transplant recipients due to immunosuppression, and may pose a continued transmission risk, especially within hospital settings. Detailed case reports including symptoms, viral load and infectiousness, defined by the presence of replication-competent viruses in culture, provide an opportunity to examine the relationship between clinical course, burden and contagiousness, and provide guidance on release from isolation.

OBJECTIVES

To investigate the relationship between serial SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (Ct) value or cycle of quantification value, or other measures of viral burden and the likelihood and duration of the presence of infectious virus based on viral culture, including the influence of age, sex, underlying pathologies, degree of immunosuppression, and/or vaccination on this relationship, in transplant recipients.

METHODS

LitCovid, medRxiv, Google Scholar and the World Health Organization COVID-19 database were searched from 1^st November 2019 to 26^th October 2022. Studies reporting relevant data (results from serial RT-PCR testing and viral culture data from the same respiratory samples) for transplant recipients with SARS-CoV-2 infection were included in this systematic review: Methodological quality was assessed using five criteria, and the data were synthesized narratively and graphically.

RESULTS

Thirteen case reports and case series reporting on 41 transplant recipients (22 renal, five cardiac, one bone marrow, two liver, one bilateral lung and 10 blood stem cell) were included in this review. A relationship was observed between proxies of viral burden and likelihood of shedding replication-competent SARS-CoV-2. Three individuals shed replication-competent viruses for >100 days after symptom onset. Lack of standardization of testing and reporting platforms precludes establishing a definitive viral burden cut-off. However, the majority of transplant recipients stopped shedding replication-competent viruses when the Ct value was >30 despite differences across platforms.

CONCLUSIONS

Viral burden is a reasonable proxy for infectivity when considered within the context of the clinical status of each patient. Standardized study design and reporting are essential to standardize guidance based on an increasing evidence base.

Liver resection in a patient with persistent positive PCR test for coronavirus disease 2019 (COVID-19): a case report

BACKGROUND

The perioperative mortality rate is high in patients with coronavirus disease 2019 (COVID-19), and infection control measures for medical care providers must be considered. Therefore, the timing for surgery in patients recovering from COVID-19 is difficult.

CASE PRESENTATION

A 65-year-old man was admitted to a hospital with a diagnosis of moderate COVID-19. He was transferred to our hospital because of risk factors, including heavy smoking history, type 2 diabetes mellitus, and obesity (BMI 34). Vital signs on admission were a temperature of 36.1 °C, oxygen saturation > 95% at rest, and 94% on exertion with 3 L/min of oxygen. Chest computed tomography (CT) showed bilateral ground-glass opacities, predominantly in the lower lungs. Contrast-enhanced abdominal CT incidentally revealed a liver tumor with a diameter of 80 mm adjacent to the middle hepatic vein, which was diagnosed as hepatocellular carcinoma (HCC). After being administered baricitinib, remdesivir, dexamethasone, and heparin, the patient's COVID-19 pneumonia improved, his oxygen demand resolved, and he was discharged on day 13. Furthermore, the patient was initially scheduled for hepatectomy 8 weeks after the onset of COVID-19 following a discussion with the infection control team. However, 8 weeks after the onset of illness, a polymerase chain reaction (PCR) test was performed on nasopharyngeal swab fluid, which was observed to be positive. The positive results persisted till 10 and 11 weeks after onset. Both Ct values were high (≥ 31) out of 45 cycles, with no subjective symptoms. Since we determined that he was no longer contagious, surgery was performed 12 weeks after the onset of COVID-19. Notably, medical staff wearing personal protective equipment performed extended anatomical resection of the liver segment 8 ventral area in a negative-pressure room. The patient had a good postoperative course, with no major complications, including respiratory complications, and was discharged on postoperative day 14. Finally, none of the staff members was infected with COVID-19.

CONCLUSIONS

We reported a case regarding the timing of surgery on a patient with persistently positive PCR test results after COVID-19, along with a literature review.

COVID-19 isolation strategies: What have we learned

Since the start of the COVID-19 pandemic, infection prevention and control policies have significantly differed between different public health organization and have been complicated by the emergence of new data on Variants of Concern (VOC). Here, we try to highlight the different strategies for isolating patients with COVID-19 and point-out the evolution of such strategies over time, mainly for mildly or moderately severe SARS-CoV-2 infected patients.

In silico prediction and experimental evaluation of potential siRNAs against SARS-CoV-2 inhibition in Vero E6 cells

Objective

The acute cases of pneumonia (COVID-19) were first reported from China in December 2019, and the pathogen was identified as SARS-CoV-2. Currently, many vaccines have been developed against this virus by using multiple genes, applying different platforms, and used for the vaccinations of the human population. Spike protein genes play an important role in host cell attachment and viral entry and have been extensively used for the development of vaccine and antiviral therapeutics. Short interfering RNA is also known as silencing RNA and contribute a significant role to regulate the expression of a specific gene. By using this technology, virus inhibition has been demonstrated against many viral diseases.

Methods

In this work, we have reported the Insilico prediction, designing, and experimental validation of siRNAs antiviral potency against SARS-CoV-2-S-RBD. The siDirect 2.0 was selected for siRNAs prediction, and secondary structure was predicted by RNAfold while the HNADOCK was used for molecular docking analysis and specific binding of siRNAs to the selected target. We have used and evaluated four siRNAs for cellular toxicity and determination of antiviral efficiency based on the Ct value of q-real-time PCR in Vero E6 cells.

Results

Based on the experimental evaluation and analysis of results from generated data, we observed that there is no cytotoxicity for any tested siRNAs in Vero E6 cells. Total four siRNA were filtered out from twenty-one siRNAs following the strict selection and scoring criteria. The better antiviral efficiency was observed in 3rd siRNAs based on the Ct value of q-real-time PCR. The results that emerged from this study encouraged us to validate the efficiency of these siRNAs in multiple cells by using alone and in a combination of two or more siRNAs to inhibit the SARS-CoV-2 proliferation.

Conclusion

The Insilico prediction, molecular docking analysis provided the selection of better siRNAs. Based on the experimental evaluation only 3rd siRNA was found to be more effective than others and showed better antiviral efficiency. These siRNAs should also be evaluated in other cell lines either separately or in combination against SARS-CoV-2 to determine their antiviral efficiency.

Duration of SARS-CoV-2 shedding and infectivity in the working age population: a systematic review and meta-analysis

BACKGROUND

During the COVID-19 pandemic, working age individuals have been implicated in sustaining the resurgence of SARS-CoV-2 infections, and multiple outbreaks have been observed in several occupational settings. In this regard, Occupational Physicians play a crucial role in the management of infected workers, particularly in the safe return-to-work of subjects after clinical resolution. To this end, knowledge of the duration of the infective phase in the working age population is essential, taking into account previous evidence suggesting that PCR positivity does not coincide with virus viability.

METHODS

A systematic review and meta-analysis, searching major scientific databases, including PubMed/MEDLINE, Scopus and Web of Science, were performed in order to synthesize the available evidence regarding the mean and maximal duration of infectivity compared to the mean and maximal duration of viral RNA shedding. A subgroup analysis of the studies was performed according to the immunocompetent or immunocompromised immune status of the majority of the enrolled individuals.

RESULTS

Twenty studies were included in the final qualitative and quantitative analysis (866 individuals). Overall, a mean duration of RT-PCR positivity after symptom onset was found equal to 27.9 days (95%CI 23.3-32.5), while the mean duration of replicant competent virus isolation was 7.3 days (95%CI 5.7-8.8). The mean duration of SARS-CoV-2 shedding resulted equal to 26.5 days (95%CI 21.4-31.6) and 36.3 days (95%CI 21.9-50.6), and the mean duration of SARS-CoV-2 infectivity was 6.3 days (95%CI 4.9-7.8) and 29.5 days (95%CI 12.5-46.5), respectively considering immunocompetent and immunocompromised individuals. The maximum duration of infectivity among immunocompetent subjects was reported after 18 days from symptom onset, while in immunocompromised individuals it lasted up to 112 days.

CONCLUSIONS

These findings suggest that the test-based strategy before return-to-work might not be warranted after 21 days among immunocompetent working age individuals, and could keep many workers out of occupation, reducing their livelihood and productivity.

Duration of viable SARS-CoV-2 shedding from respiratory tract in different human hosts and its impact on isolation discontinuation polices revision; a narrative review

BACKGROUND

The duration of viable viral shedding is important to be defined in regards of viral transmission in SARS-CoV-2 infection with the backdrop of the current worldwide effort for revising isolation polices and establishing the duration of infectiousness.

METHODS

In this review we searched databases including Medline and google scholar for research articles published between January 2020 and January 2022. We included case reports, case series, cross sectional, cohort, and randomized control trials that reported the duration of shedding of viable SARS-CoV-2 virus. After evaluating the criteria for inclusion, 32 articles (2721 patients) were included.

RESULT

This review showed that the median for the last day of successful viral isolation was 11 (8.5-14.5 95% CI) , 20 (9.0-57.5 95 %CI), 20 (9.0-103 95 %CI) for the general population, critical patients and immunocompromised individuals, respectively, with significant association between prolonged viral shedding, disease severity (P-Value 0.024) and immunosuppressive status (P-Value 0.023).The corresponding higher cutoff of CTv to culturable virus ranged between 26.25 and 34.00 (95% confidence interval) with median of 30.5, and higher values were observed when critical (25.0-37.37 95 %CI) and immunocompromised patients (20.0-37.82 95 %CI) have been excluded, this deviation did not represent a statistical significance (P-Value 0.997 and 0.888) respectively.

CONCLUSION

Our review highlights that repeating SARS-CoV-2 viral RNA test solely in recovering patients has no importance in determining infectivity and emphasizes the individualization of de-isolation decisions based on the host factors and a combined symptom and testing-based approaches with the later benefiting most of correlation with recently introduced rapid antigen test. Our finding in the review also opposes the most recent CDC Guidance on shortening isolation duration in term of the last days of viable transmissible virus, therefore caution should be considered when revising such protocols.

Assessment of the Health-Promoting Behaviors of Hospitalized Patients with Non-Communicable Diseases During the Second Wave of COVID-19

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has affected the health-related behaviors of patients with non-communicable diseases (NCDs). Thus, the factors predicting the health-promoting behaviors (HPBs) of hospitalized patients with NCDs during the second wave of COVID-19 should be examined.

OBJECTIVE

The aims of this study were to determine the relationships among the patients' characteristics, perceived self-efficacy, social support, perception of the benefits of and barriers, and HPBs, and to determine the predictive factors of HPBs among hospitalized patients with NCDs during the second wave of COVID-19.

PATIENTS AND METHODS

The study had a cross-sectional predictive correlational design and included 250 patients with NCDs 18 years of age or older hospitalized in a tertiary hospital in Thailand. Descriptive statistics, the chi-square test, the Pearson's correlation coefficient, and stepwise multiple linear regression were used for data analysis.

RESULTS

Most of the participants had a cardiovascular disease (34.0%). Followed by diabetes (28.8%), cancer (11.2%), hypertension (10.0%), heart disease (9.6%), or chronic obstructive pulmonary disease (6.4%) and had a moderate level of overall HPBs (M = 106.09; SD = 4.66). Among the six components of the HPBs, the participants achieved the moderate levels in nutrition, interpersonal relations, spiritual growth, and stress management, and low levels in physical-activity and health responsibility. The patients' perception of the benefits and barriers to the adoption of HPBs and perceived self-efficacy and social support were able to predict their HPBs, accounting for approximately 38.0% of the variance of such behaviors.

CONCLUSION

On the basis of our study's results, we suggest that researchers, multidisciplinary teams, the government, and policymakers establish effective interventions, guidelines, and policies for the development of HPBs to prevent and control the spread of COVID-19 particularly among patients with NCDs, and to improve their capacity for high-quality and continuing self-care.