About COVID-19 Study Register

What is Cochrane's COVID-19 Study Register?

Cochrane's COVID-19 Study Register is a freely-available, continually-updated, annotated reference collection of human studies* on COVID-19, including interventional, observational, diagnostic, prognostic, epidemiological, qualitative and economic designs.

The aim of the register is to support rapid evidence synthesis, including Cochrane's work on Rapid Reviews in response to COVID-19.

To enable discovery, we add vocabulary descriptors to references from Cochrane's PICO ontology. Please note: PICO annotations are available initially for interventional studies and randomized controlled trials, with other study designs to follow.

* Please note: the register will not include in-vitro study references.   

Where do we source our references?

The three primary data sources for Cochrane's COVID-19 Study Register are the publicly available trial registry platforms: ClinicalTrials.gov and the WHO's International Clinical Trials Registry Platform (ICTRP), and the National Library of Medicine's bibliographic database PubMed.

Secondary data sources are assessed continuously for unique content and data quality. Currently in production are preprint records from medRxiv compiled by the Stephen B. Thacker CDC Library COVID-19 Research Articles Downloadable Database.

We also monitor Retraction Watch daily. Retraction notices and expressions of concerns are added as references to studies in the register.

We’ll update our list of sources as new references are included in the register.  

How frequently is the register updated? 

Currently, we are updating ClinicalTrials.gov and PubMed records daily (Monday-Friday), and ICTRP records weekly (on Fridays). 

What enhancements are coming? 

We are making the COVID-19 Study Register available with basic search, browse and export capabilities to support underway and urgent evidence synthesis. In the coming weeks, we will:

  • Add study references from additional sources, including grey literature repositories and preprint archives, to ensure the comprehensiveness of the register
  • Complete PICO annotations on all study designs
  • Develop alerting and updating features to support ongoing evidence surveillance 

What are our search methods? 

Search Strategies: Search strategies are designed for maximum sensitivity, to retrieve all human studies on COVID-19. No language limits are applied. Strategies will be updated to account for changes to the COVID-19 study register's eligibility criteria, changes to database interfaces and ongoing search performance assessments.

The PubMed strategy was designed by Robin Featherstone MLIS, Information Specialist Cochrane Editorial and Methods Department, and peer reviewed by Douglas Salzwedel MLIS, Information Specialist and Assistant Managing Editor Cochrane Hypertension. The PubMed strategy was validated on May 13 against a "gold standard" sample of 184 known PubMed study references on COVID-19. Sensitivity was 1.0 (i.e. all references in the sample were retrieved). 


Strategy (last updated 13 May 2020)




Health topic: 2019-nCov / COVID-19


("2019 nCoV"[tiab] OR 2019nCoV[tiab] OR "2019 novel coronavirus"[tiab] OR ((coronavirus[tiab] OR "corona virus"[tiab]) AND (Huanan[tiab] OR Hubei[tiab] OR Wuhan[tiab])) OR "coronavirus-19"[tiab] OR "coronavirus disease-19"[tiab] OR "coronavirus disease-2019"[tiab] OR "COVID 19"[tiab] OR COVID19[tiab] OR "nCov 2019"[tiab] OR "new coronavirus"[tiab] OR "new coronaviruses"[tiab] OR "novel coronavirus"[tiab] OR "novel coronaviruses"[tiab] OR "novel corona virus"[tiab] OR "SARS-CoV2"[tiab] OR "SARS CoV-2"[tiab] OR SARSCoV2[tiab] OR "SARSCoV-2"[tiab] OR "SARS-coronavirus-2"[tiab] OR "SARS-like coronavirus"[tiab] OR "Severe Acute Respiratory Syndrome Coronavirus-2"[tiab] OR "COVID-19"[nm] OR "COVID-19 drug treatment"[nm] OR "COVID-19 diagnostic testing"[nm] OR "COVID-19 serotherapy"[nm] OR "COVID-19 vaccine"[nm] OR "LAMP assay"[nm] OR "severe acute respiratory syndrome coronavirus 2"[nm] OR "spike protein, SARS-CoV-2"[nm]) NOT ("animals"[mh] NOT "humans"[mh]) NOT (editorial[pt] OR newspaper article[pt])

* Automatic term mapping links results for 2019-nCoV, 2019 novel coronavirus, SARS-CoV-2, severe acute respiratory syndrome coronavirus 2


Trial registry records are sourced from ClinicalTrials.gov and the World Health Organization's International Clinical Trial Registry Platform (ICTRP). The National Library of Medicine is the source of PubMed bibliographic records; and Cold Spring Harbor Laboratory, BMJ, Yale are the source of medRxiv preprint records. We acknowledge the Stephen B. Thacker CDC Library for compiling and providing the medRxiv preprint records. 

Our development partners are Data Language and Metaxis

Notes on Modifications

Study design characteristics and controlled vocabulary descriptors are added to source records to enable advanced search features.

Terms and Conditions of Use / Disclaimer

All persons reproducing, redistributing, or making commercial use of this information are expected to adhere to the terms and conditions asserted by the copyright holder. Transmission or reproduction of protected items beyond that allowed by fair use as defined in the copyright laws requires the written permission of the copyright owners.

Cochrane does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed.


Please direct any questions or comments about Cochrane's COVID-19 Study Register to covid-19-register@cochrane.org


Page last updated: Jun 22, 2020