The evidence on transmission dynamics of COVID-19 from pre- and asymptomatic cases: protocol for a systematic review (Version 2)

Preprint

Background The role of forward transmission of infection from cases of SARS-CoV-2 who remain without symptoms and signs throughout the active phase of the disease (asymptomatic) and those who have not developed symptoms or signs when surveyed (presymptomatic) is at present unclear, despite the important role that they may play in transmission dynamics.

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 for additional relevant studies. We will include studies of people exposed to SARS-CoV-2 within 2-14 days of close contact or suspected community or institutional exposure to index asymptomatic or pre-symptomatic infected individuals, as defined in each study along with secondary case(s) infected. We will include only studies that provide proof of transmission outcome using culturable virus and /or genetic sequencing. The inclusion of this higher-quality evidence aims to overcome the methodological shortcomings of lower quality studies. We will assess the microbiologic or genetic sequencing evidence in an effort to inform the quality of the chain of transmission evidence and adequacy of follow up of sign 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 on summarising the evidence and drawing conclusions as to the quality of the evidence.

Authors: Plüddemann, A; Jefferson, T; Spencer, EA; Brassey, J; Rosca, EC

• Publication status: Published
• Peer review status: Peer reviewed
• Preprint server: medRxiv
• Publication date: 2021-07-16
• DOI: 10.1101/2021.05.06.21256615
• Language: English
• Keywords: COVID-19; SARS-CoV-2; transmission; levels of evidence