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Research led by Professor Carl Heneghan and Epidemiologist, Tom Jefferson, provides a rapid summary and evaluation of relevant data around the transmission of SARS-CoV-2, reporting on important policy implications and highlighting areas of urgently needed research.

Coronavirus disease COVID-19 outbreak. Microscopic view of a infectious virus. SARS-CoV-2 virus cell. 3D Rendering © Shutterstock

The multidisciplinary team has considerable expertise in evidence synthesis and the evaluation of acute respiratory infections. Both Carl Heneghan and Tom Jefferson have worked together for over a decade having been authors of the Tamiflu reviews and are Clinical Editors for the Cochrane Acute Respiratory Infections Group.

The team publishes updates with recommendations for policy, and a series of hypotheses to be tested by further work. 

The project so far

This project is split into two key areas of focus, 'Transmission of SARS-CoV-2' and 'Viral cultures for COVID-19'. 

Transmission of SARS-CoV-2

The first phase of four reviews, funded by WHO, have now been published on transmission causality. The transmission areas include airborne, contact and droplet, orofecal, vertical and fomite, with asymptomatic and presymptomatic transmission coming soon. All are concluded on our project page. The 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 World Health Organization guidance and scientific documents.

The reviews:

SARS-CoV-2 and the Role of Airborne Transmission: Systematic review (published 15 days after submission)

SARS-CoV-2 and the role of Orofecal Transmission: Systematic review (published 22 days after submission)

SARS-CoV-2 and the Role of Fomite Transmission: Systematic Review (published 22 days after submission)

SARS-CoV-2 and the Role of Close Contact in Transmission: Systematic Review

All reviews can be accessed on the project homepage

Viral cultures for COVID-19

Complete live viruses are necessary for transmission. Prospective routine testing should be used to define the reliability of PCR for assessing infectious potential. 

This project involved systematically reviewing 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. This review was not funded by the WHO.

View the project homepage for key outcomes, systematic reviews and related articles.

Additional funding 

NIHR SPCR Evidence Synthesis Working Group project 390

What's next?

The team is working reviews of the evidence of ertial transmission (mother to baby), transmission in aircraft and transmission of variants, as well as periodic updates of all reviews making the project a comprehensive transmission causality body of evidence of SARS-CoV-2.