In 2020 ESICM carried out its most ambitious investigation yet, UNITE–COVID-19. This one-day multi-centre, international anonymised point prevalence study, was designed to discover more about the burden of COVID-19 in ICUs around the world, including regional differences, the current management of critically ill patients with COVID-19 and variability in treatment, clinical characteristics and outcomes. 

Now the investigation must continue. UNITE – COVID ed2021 looks at the effects of the second and third waves of Covid – 19 in ICUs across the world. For this, we need the benefit of your knowledge and experience. Whether you participated last year or are enrolling for the first time, please get involved.


This is a multicenter, international, anonymized point prevalence study.
This study is for COVID-19 patients who were present in the ICU on the day between January 1st and June 1st, 2021 with the highest number of COVID-19 patients in the unit or in any other area under the care of the critical care team.
Subjects who fulfill all eligibility criteria, and none of the exclusion criteria, detailed in the relevant section of this protocol, will be included in the study.
Data will be entered into the database anonymously.
Data will consist of two core elements: Center data (to be completed once) and Patient data.
For different domains with specific, highly relevant and un(der)explored ICU research questions, a focused data set is to be completed.


This study will provide answers to the following questions from a global perspective:

What is the burden of COVID-19 in ICUs around the world?
How are patients with COVID-19 now managed around the world?
What are the outcomes of ICU patients with COVID-19?
What is the incidence of specific patterns such as respiratory phenotypes, AKI, infectious complications, thromboembolic events (venous and arterial), neurological complications and cardiac complications


COVID-19 is arguably the biggest challenge critical care medicine has been confronted with since its conception. Critical care services around the world are flooded by patients presenting with severe respiratory failure who require prolonged treatment in the ICU. Despite the support provided, outcomes are poor, particularly in ventilated patients.

Many unanswered questions remain regarding the pathophysiology of COVID-19, particularly in severely ill patients. No evidence-based treatment is currently available, yet different often experimental therapies are administered to patients.

As experience grows, new phenotypes are recognized, and unreported complications are observed in the most severely ill patients. Although many registries are currently including patients, few of them focus on ICU patients and their specific treatments and newly observed complications and challenges.

Although the pandemic may appear on its return in many countries that are now easing the restrictions that were put in place to limit the spread of the disease, it can be expected that COVID-19 will be a continued challenge in ICUs globally until a safe and effective vaccine is found. Efforts to study the disease should continue in order to advance our understanding of the disease as well as improve treatment options.


Select the day between  January 1st and June 1st 2021 with the highest number of critically ill COVID-19 patients in the unit or in any other area in the hospital under the care of  the critical care team

Study duration: 1 day (with 60-day follow up)

Eligibility criteria

For details on inclusion and exclusion criteria, please consult  the study protocol here.

COVID-19 confirmed diagnosis through PCR or equivalent diagnostic technique.

Data collection

For each participating centre, we will collect centre data as detailed in CenterData CRF.

Data will be recorded regarding current nurse/patient ratio, MD/patient ratio, number of beds, 24h intensivist staffing, and hospital type, as well as resources available and capacity.

Data entry will be facilitated by an electronic Case Report Form (eCRF). No patient-identifying information will be collected.

Access to the database is protected via a TLS encrypted connection and a login/password combination. The data will be stored securely and all procedures regarding data management will comply with General Data Protection Regulation (GDPR) 2016/679/EU. The eCRF platform is licensed from ClinFile and administered by ESICM.

The eCRF platform is GDPR compliant.

Do I need IRB approval?

Where required by local legislation or regulation, the study protocol will be submitted to the local ethics committee for approval.  Whereas UNITE-COVID-19 is a retrospective no-risk study, a waived informed consent model can be used. Please find the Principal Investigator’s Ethical Approval (Belgium) here. The amendment for the 2021 edition will be available shortly.

Who owns and can access the collected data? 

Each site investigator is responsible for their own data and may request an export of their locally collected data after the UNITE-COVID-19 database is locked. The request should be addressed to the Principal Investigator.
After the primary UNITE-COVID-19 manuscript is published, investigators may publish their local data.

Authorship and publication rules: Steering Committee members will be part of the writing committee and listed as authors of the final manuscript. The Unite Covid Steering Committee decided to revise how best to acknowledge the collaborators in order to appropriately thank you and your team for your efforts. Any centre that has obtained ethics committee approval (if necessary according to local regulations) and that included at least 2 patients can have 1 collaborator mentioned in the list of collaborators attached to the publication of the primary paper. In case more cases are included the following applies: 20 or more patients: 2 collaborators; 50 or more patients: 3 collaborators; 100 or more patients: 4 collaborators

Is there any financial compensation?

There is no financial compensation for participation. Participation in the trial is completely voluntary.

How do I participate?

Registration is closed.


Conway Morris A, Kohler K, De Corte T, Ercole A, De Grooth HJ, Elbers PWG, Povoa P, Morais R, Koulenti D, Jog S, Nielsen N, Jubb A, Cecconi M, De Waele J, ESICM UNITECOVIDI. Co-infection and ICU-acquired infection in COIVD-19 ICU patients: a secondary analysis of the UNITE-COVID data set. Crit Care. 2022;26:236.

Greco M, De Corte T, Ercole A, Antonelli M, Azoulay E, Citerio G, Morris AC, De Pascale G, Duska F, Elbers P, Einav S, Forni L, Galarza L, Girbes ARJ, Grasselli G, Gusarov V, Jubb A, Kesecioglu J, Lavinio A, Delgado MCM, Mellinghoff J, Myatra SN, Ostermann M, Pellegrini M, Povoa P, Schaller SJ, Teboul JL, Wong A, De Waele JJ, Cecconi M, ESICM UNITE-COVIDI. Clinical and organizational factors associated with mortality during the peak of first COVID-19 wave: the global UNITE-COVID study. Intensive Care Med. 2022;48:690-705.

UNITE-COVID-19 Steering Committee Members

The list can be downloaded here

Any further questions?

Please read the Frequently Asked Questions (FAQs) document.

You can contact the ESICM office: or


  • Protocol (last version dated 28 June 2021). It highlights the new dates of the 2021 edition and a new secondary objective which is to compare patient characteristics, treatment and outcomes between the 2020 and 2021 waves of Covid-19.
  • Ethical approval (Belgium – Principal Investigator). –Amendment approval (Upload 2 July 2020). The 2021 amendment is available here (7 July 2021).
  • FAQs (last update 14 Sept 2020.)
  • National Coordinators List (last update 31 Jan. 2022)
  • Patient CRF (last version dated 28 June 2021. The only change compared to the one of 2020 is the 3rd question in the domain rehabilitation: Was the patient mobilized during total ICU stay?)
  • Center CRF (uploaded 26 May. no change compared to the 2020 one edition)