ABSTRACT
Background. The extent to which the oro-faecal route contributes to the transmission of SARS-CoV-2 is not established. Methods: We systematically reviewed the evidence on the presence of infectious SARS-CoV-2 in faeces and other gastrointestinal sources by examining studies that used viral culture to investigate the presence of replication-competent virus in these samples. We conducted searches in the WHO Covid-19 Database, LitCovid, medRxiv, and Google Scholar for SARS-CoV-2 using keywords and associated synonyms, with a search date up to 28th of November 2023. Results: We included 13 studies involving 328 COVID-19 subjects - providing 314 faecal or rectal swab SARS-CoV2 positive samples tested also with viral culture. The methods used for viral culture across the studies were heterogeneous. Three studies (2 cohorts and 1 case-series) reported observing replication-competent SARS-CoV-2 confirmed by quantitative RT-PCR (qPCR) and whole genome sequencing, and qPCR including appropriate cycle threshold changes. Overall, six (1.9%) of 314 faecal samples subjected to cell culture showed replication-competent virus. One study found replication competent samples from one immunocompromised patient. No studies were identified demonstrating direct evidence of oro-faecal transmission to humans. Conclusions: Our review found a relatively low frequency of replication-competent SARS-CoV-2 in faecal and other gastrointestinal sources. Although it is biologically plausible, more research is needed, using standardized cell culture methods, control groups, adequate follow-up and robust epidemiologic methods, including whether secondary infections occurred, to determine the role of the oro-faecal route in the transmission of SARS-CoV-2.
Subject(s)
COVID-19 , CoinfectionABSTRACT
Rationale for the review: COVID-19 treatment can worsen parasitic disease in patients with coinfection. Consequently, there is a need to investigate the infection with SARS CoV 2 and Strongyloides. We aim to systematically review clinical and laboratory features of COVID 19 and Strongyloides coinfection, to investigate possible interventions and outcomes in this pathology. Also, we aim to identify difficulties in managing the parasitic disease manifestations in this context and to emphasize research gaps requiring further attention. Methods: We will search two electronic databases (LitCOVID, and WHO COVID 19) and will include studies on SARS CoV 2 and Strongyloides coinfection. We will adapt the WHO UMC system for standardized case causality assessment to evaluate if using corticosteroids or other immunosuppressive drugs in COVID 19 patients determined acute strongyloidiasis manifestations. Expected results: We will present the evidence in three distinct packages: study description, methodological quality assessment and data extracted. We will summarize the evidence and will draw conclusions as to the quality of the evidence.
Subject(s)
COVID-19 , Strongyloidiasis , Severe Acute Respiratory Syndrome , Parasitic DiseasesABSTRACT
This is the protocol for a systematic review focussing on people receiving solid organ or hematopoietic stem cell transplants. Our research questions are as follows: What is the relationship between serial PCR Ct value or other measures of viral burden, and the likelihood and duration of the presence of infectious virus from viral culture, among transplant recipients with SARS-CoV-2 infection? What is the influence of age, sex, underlying pathologies, degree of immunosuppression, vaccination status, COVID-19 symptoms and COVID-19 disease course on viral burden and the likelihood of presence of infectious SARS-CoV-2? We will include single studies reporting serial Cts from sequential rt-PCR testing or other measures of viral burden such as RNA gene copies of respiratory samples (from nasopharyngeal specimens) along with viral culture data on the same samples, from patients about to receive a transplant or who are post transplant with SARS-CoV-2 infection.
Subject(s)
COVID-19 , Severe Acute Respiratory SyndromeABSTRACT
Background: Maritime and river travel, including cruise ships, have been implicated with spreading viruses through infected passengers and crew. Given the novelty of the SARS-CoV-2 infection, early cruise ship travel transmission models of spread are based on what is known of the dynamics of other respiratory viral infections. Our objective is to provide a rapid summary and evaluation of relevant data on SARS-CoV-2 transmission aboard cruise ships, report policy implications, and highlight research gaps requiring attention. Methods: We will search LitCovid, medRxiv, Google Scholar, and the WHO Covid-19 database using COVID-19, SARS-CoV-2, transmission, and cruise ship appropriate synonyms. We will also search the reference lists of included studies for additional relevant studies. We will include studies reporting onboard SARS-CoV-2 transmission from passengers and/or crew to passengers and/or crew. We will consider any potential transmission mode. We will assess study quality based on five criteria and report important findings. The outcome will consist of the onboard cruise ships transmission of SARS-CoV-2. We will provide a narrative summary of the data and report the outcomes, including quantitative estimates where feasible and relevant. Where possible, compatible datasets may be pooled for meta-analysis. Expected results: We will present the evidence in three distinct packages: study description, methodological quality assessment and data extracted. We will summarize the evidence and will draw conclusions as to the quality of the evidence.
Subject(s)
COVID-19 , Respiratory Tract Infections , Pasteurellosis, PneumonicABSTRACT
BackgroundVertical transmission of SARS-CoV-2 has been reported but does not appear to be common. This study aims to systematically review the evidence for vertical transmission of SARS-CoV-2. MethodsThis review is part of an Open Evidence Review on the transmission dynamics of SARS-CoV-2 and the role of intrauterine mother to fetus transmission. Literature searches were performed in the WHO Covid-19 Database, LitCovid, medRxiv, and Google Scholar for SARS-CoV-2 using keywords and associated synonyms, search date up to 20 December 2020, no language restrictions. ResultsWe included 106 studies assessing vertical transmission of SARS-CoV-2 from pregnant women to their neonates: these studies comprised 40 reviews (21 fulfilled systematic review methodology, including risk of bias assessment of included studies) and 66 primary studies including 32 case reports (of up to two cases) and 34 prospective and retrospective cohort studies, prospective and retrospective case series, observational studies (including asymptomatic screening), database studies and a quality improvement project. Almost all were conducted in a hospital setting. The 32 case reports were considered to be at high risk of bias, due to the study design; across the 34 remaining primary studies, risk of bias was low to moderate. Sixteen case reports examined vertical transmission, which was not related to maternal symptomatology. For the cohort and case series studies, the percentage of positive neonates ranged from 0% to 22% across the studies. Twenty studies reported no positive vertical transmission. Three studies that reported the highest positivity rates of 11%, 15% and 22% had specifically selected neonates with a positive test (within up to 35 days) within the study population and were therefore more selective populations. Across the cohort and case series studies there were 65/2391 (2.7%) neonates born to mothers with a diagnosis of COVID-19 tested positive for SARS-CoV-2 within 24 hours of birth. No evidence correlated maternal symptomatology to vertical transmission. Mode of delivery did not correlate with rates of vertical transmission. Of 25 studies, 7 identified SARS-CoV-2 in placental tissue; some of these did not demonstrate vertical transmission to the neonate. No study reported the results of viral culture to detect SARS-CoV-2. ConclusionsThe results of these studies indicate that vertical transmission is possible, but is not frequent, and factors that influence when vertical transmission occurs are unknown. Further studies using standardised methods to establish viral infection are needed to establish vertical transmission rates and to assess clinical and other conditions affecting transmission.
Subject(s)
COVID-19ABSTRACT
BackgroundAir travel may be associated with the spread of viruses via infected passengers and potentially through in-flight transmission. Given the novelty of the SARS-CoV-2 virus, transmission associated with air travel is based on what is known about the dynamics of transmission of other respiratory virus infections, especially those due to other coronaviruses and influenza. Our objective was to provide a rapid summary and evaluation of relevant data on the transmission of SARS-CoV-2 aboard aircraft, report important policy implications, and highlight research gaps requiring urgent attention. MethodsThis review is part of an Open Evidence Review on Transmission Dynamics of SARS-CoV-2. We searched LitCovid, medRxiv, Google Scholar, and the WHO Covid-19 database from 1 February 2020 to 27 January 2021 and included studies on the transmission of SARS-CoV-2 aboard aircraft. We assessed study quality based on five criteria and reported important findings. ResultsWe included 18 studies on in-flight transmission of SARS-CoV-2, representing 130 unique flights and two studies on wastewater from aircraft. The overall quality of reporting was low. Two wastewater studies reported PCR-positive SARS-CoV-2 samples, but with relatively high Cycle threshold values ranging from 36 to 40. The definition of an index case was very heterogeneous across the studies. The proportion of contacts traced ranged from 0.68% to 100%. In total, the authors successfully traced 2800/19729 passengers, 140/180 crew members, and 8/8 medical staff. Altogether, 273 index cases were reported, with 64 secondary cases. No secondary cases were reported in three studies, each investigating one flight. The secondary attack rate among the studies that followed up >80% of the passengers and crew (including data on 10 flights) varied between 0% and 8.2%. The included studies reported on the possibility of SARS-CoV-2 transmission from asymptomatic, pre-symptomatic, and symptomatic individuals. Viral cultures were performed in two studies, with 10 positive results reported. Genomic sequencing and phylogenetic analysis were performed in individuals from four flights, with the completeness of genomic similarity ranging from 81-100%. ConclusionCurrent evidence suggests that SARS-CoV-2 can be transmitted during aircraft travel, but the published data do not permit any conclusive assessment of the likelihood and extent. Furthermore, the quality of evidence from most published studies is low. The variation in study design and methodology restricts the comparison of findings across studies. Standardized guidelines for conducting and reporting future studies of transmission on aircrafts should be developed.
Subject(s)
COVID-19ABSTRACT
Background The role of cases of SARS-CoV-2 who remain without symptoms throughout the active phase of the disease (asymptomatics) and those who have not developed symptoms yet when surveyed (pre-symptomatics) is at present unclear, despite the important role that they may play in infecting third parties. There is also a lack of clarity on the role of pauci-symptomatic persons with COVID-19 and the degree to which they may be associated with transmission compared to fully symptomatic persons. Methods We will search LitCovid, medRxiv, Google Scholar and the WHO Covid-19 database using Covid-19, SARS-CoV-2, transmission, and appropriate synonyms as search terms. We will also search the reference lists of included studies are searched for additional relevant studies. We will include studies of people exposed to SARS CoV-2 within 2-14 days (incubation time) of close contact or suspected community or institutional exposure to index asymptomatic infected individuals, as defined in each study with secondary case(s) infected. We will only include studies which provide microbiological proof of transmission outcome (culturable virus and /or genic sequencing). The inclusion of higher-quality evidence should overcome the methodological shortcomings of lower quality studies. We will assess quality of the chain of transmission evidence, microbiological proof and adequacy of follow up and symptom monitoring. Expected results We intend to present the evidence in three distinct packages: study description, methodological quality assessment and data extracted. We intend summarising the evidence and drawing conclusions