Transmission of SARs-CoV-2
Providing a rapid summary and evaluation of relevant data on the transmission of SARS-CoV-2, reporting important policy implications and highlighting areas of urgently needed research.
Our multidisciplinary team has considerable expertise in evidence synthesis and the evaluation of acute respiratory infections. Carl Heneghan, Tom Jefferson and Annette Plüddemann lead the research and have worked together for over a decade, having been authors of the Tamiflu reviews.
Transmission of SARS-CoV-2
We publish updates with recommendations for policy, and a series of hypotheses to be tested by further work. Our conclusions and expected outcomes are below the byline of each review.
The transmission areas include airborne, contact and droplet, orofecal, vertical, fomite and asymptomatic and presymptomatic transmission.
Our SYSTEMATIC REVIEWS
Impact on healthcare policy
Reference WHO registration No 2020/1077093.
The World Health Organisation funded reviews were the first phase of our project. Its objective is to undertake a series of living systematic searches and appraisal of evidence on SARS-CoV-2 modes of transmission and its related updates are informing WHO guidance and scientific documents. CH, AP and ES also receive funding support from the NIHR SPCR Evidence Synthesis Working Group project 390.
The WHO updates interim guidance (12 July 2021) on infection prevention and control (IPC) during health care when coronavirus disease (COVID-19) is suspected or confirmed, and cites CEBM work on airborne, finite and close contact transmission as well as non pharmaceutical interventions.
Intended for health workers, including managers and IPC teams at facility, national and district/provincial levels, this guidance summarizes evidence on infection prevention and control strategies and measures associated with the care for suspected or confirmed cases of COVID-19 in health facilities.
Viral cultures for COVID-19
Complete live viruses are necessary for transmission, not the fragments identified by PCR. Prospective routine testing of reference and culture specimens and their relationship to symptoms, signs and patient co-factors should be used to define the reliability of PCR for assessing infectious potential. Those with a high cycle threshold are unlikely to have infectious potential.
Read the research: Viral cultures for COVID-19 infectious potential assessment – a systematic review.
What did we do?
We systematically reviewed the evidence from studies relating SARS-CoV-2 culture with the results of RT-PCR and other variables which may influence the interpretation of the test, such as time from symptom onset
PCR testing cannot distinguish between the shedding of live virus or of viral fragments with no infectious potential. Although viral culture is difficult, time-consuming and requires specialised facilities it potentially represents the best indicator of infection and infectious potential.
21st Aug: It’s a mistake to think all positive Covid tests are the same Carl Heneghan, Tom Jefferson
14th Sep: What does a case of COVID-19 really mean? Carl Heneghan, Tom Jefferson
7th Sep: Covid-19 and the end of clinical medicine as we know it Carl Heneghan, Tom Jefferson
John Conly, Professor of Medicine, Department of Medicine (Infectious Diseases), Cumming School of Medicine, University of Calgary and Alberta Health Services
David Evans, Professor, Department of Medical Microbiology & Immunology Chair
Elena Cecilia Rosca, Associate Professor, Department of Neurology, Victor Babes University of Medicine and Pharmacy of Timisoara
Viral cultures for COVID-19 infectivity assessment – a systematic review (Update 4)
Jefferson T. et al, (2020)
Viral Cultures for Coronavirus Disease 2019 Infectivity Assessment: A Systematic Review
Jefferson T. et al, (2021), Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 73, e3884 - e3899
Director, TRIP Database